OIl pressure still drops after changing oil sending unit?

Did you check the pressure with a mechanical gauge? Does the engine make noise when there is a low pressure indicated? --- If there is pressure in the engine and going on the assumption that the indication is bad, check the ohms of the sending unit - it should remain steady. Check the voltage to the gauge it should be a steady 12-13.5 volts. --- A oil pressure gauge in actually a voltage gauge with a different face. 12 volts on the supply side and the sending unit actually varies the resistance to ground.

i have seen a bunch of these truks with this problem and what it iis there is a small screen under the oil pressure switch that gets sludge in it and stops oil from reaching your pressure sensor, remove your oil pressure sensor on rear of intake and take a small pick and pull out the screen and throw it away, reinstall our oil pressure sensor.

I have this exact problem. It is obviously oiling because there is no difference in the sound of the motor from before the problem to now. Purrs like a kitten even though the dash lights are going crazy and the guage drops to zero in about a minuet. So..My 2009 5.3L just started this crap. New sensor is $80 bucks...Question to last poster...so is it safe to remove the screen a reuse the sensor? How many times have you done this? Isnt that like putting a bad part back on after going through the pain of fixing it. It is a special order part at O'Rileys...

You can install new sensor while you have it out but if sensor is not leaking oil I would clean out pressure hole in end of sensor, throw that stupid screen away and go with it and removing screen won't hurt anything, all it does it collect sludge an plug up, the never had them before !

I have a similar (maybe different) problem... I have an 2003 avalanche 5.3 180K miles was on a road trip. leaving for home as I started "low oil pressure" warning came on for about 30 seconds as I was driving-then went off...went to first gas station..checked oil..level was fine. Drove 4 hours home..warning chime went off one other time for about 10 seconds..then off again. took it to a shop next day, when driving there, no warning messages.. He said motor is shot..suggested a reman replacement $4500. told him I needed to think about it I was gonna come pick it up. Went to pick it up. "low oil pressure"warning came on as soon as I started it, it ran 10 seconds and shut down. so I have 1 time a warning shortly after start, then another after it ran at highway speeds (power felt fine) for 4 hours..and now I got the warning at start up.. Any ideas? suggestions? I am the original owner and have maintained the truck pretty well...is the motor really shot at 180K ?

Change the oil pressure sensor (aka oil pressure sending unit). Also, if it happens to have a filter below the sensor, replace/clean that also. You'll need a 27mm deep socket, a 1/2 to 3/8 adapter, and 1 or 2 extensions. It's behind the intake manifold, near the firewall. Kind of a pain to get to. I personally filed away some of the plastic casting from the intake manifold, on the driver side to make more room... otherwise, expect a bloody knuckle (the one below your thumb). Worked great. Enjoy.

I changed the filter under the oil sending unit. I suggest carefully removing the alternator and then the intake manafold. Get a new gasket set and this will make your engine run better too with 100k miles on it. This can be done start to finish in 2 hours. It will fix your problem. If the motor does not start rattling immediately when the Guage drops it's still oiling. Just a stopped up badly designed GM sensor. CA

BTW you will need a screw or a pick to stick down in the oil sending unit hole after it is removed and pick that 2 inch long filter out of the hole. It IS NOT attached to the sending unit. You will have to coax it out.

I had the same issue but with my Oldsmobile 88. I changed the pressure sensor. What should I expect next or by changing the pressure sensor fixed my issue, because I was on a date and Bamm all the oil dropped. Next day I changed it like mentioned before and now the oil is still there. My question is. Should I expect another issue or not? Thanks in advance.

If your hydraulic lifters are in good shape you will not hear the classic no oil lifter tap until after about 15 to 20 seconds or more of no oil. Once you start hearing the tap you are doing damage to the lifters (not to mention the rest or the motor) If you do not have the ability to determine beyond a doubt that oil is really flowing take it to someone who can or you are going to toast your motor.

I have had the same issue with my 08 Chevy but NOTHING has fixed it! We replaced the OPSU 3 times. The filter wasn't even in place when the unit was changed. Check engine light still came back on. So my whole engine was taken apart and cleaned, filters changed, oil pump changed and anything and everything that could be done has been done. After the full cleaning the light went off for long enough for me to pass emissions and had stayed off for 3 months... And you guessed it... Check engine light is back on. Any suggestions??

Forget replacing the sensor. Here is the deal. There is a filter that sits just below the sensor in the intake manifold that gets clogged preventing the sensor from reading the pressure. I just bought one for $12.00 from the dealer. My dealer wants $300.00 to replace the sensor and filter. Not sure I want to make a mess of my hands!

Is that filter in every engine? I've got a 2004 Sierra with the 5.3. New mains, new rod bearings, new rings, new oil pump, new lifters, reman heads. Oil pressure fluctuates from 20-45 with no rhyme or reason. Doesn't matter whether or not the engine rpm's are up or at idle.

Certainly sounds like the oil pressure sensor filter. That is how it started for me. Then got progressively worse as the filter became more clogged. I would go to the parts department at a dealer and let them get a blowup of your engine intake manifold and will be surprised if it is not there. Should be in the back of the manifold.

2001 tahoe reading highoil pressure changed oil and sending unit still the same.. guage wount drop back down after shutting engine off

I hate to be the bearer of bad news but your crankshaft bearings are shot I have the same problem with my 2003 Tahoe this is due to inferior metals that they put in the Bering crankshaft low bid I guess. Oh by the way I bought new in 2003 have only 137K and used synthetics only every 5K. I hate GM

Don't know about early models BUT it is the FILTER under the oil pressure sending unit getting clogged. Had it replaced 3 times by the dealer under warranty. They even confirmed that is what was. Mine is a 6.0 2007 new body style Silverado. Change your oil allot.

I have an 09 GMC Sierra with a 5.3 liter. I've recently had oil consumption problems took it to the dealer they ended up putting new piston and rings new lifters and since I've got it back it tIcks really bad on dry start. Once oil pressure builds up it goes away, but it seem that it takes the pressure a little longer to build than usual. Warranty just ran out.. any suggestions?

I have been having this identical problem, however the pressure only drops when I weight in the back or I am towing heavy....outside of that, oil pressure always stays on target. still the filer / screen?

I just had the same problem of no oil pressure. '09 5.3 ltr. Took to local guy, he suspected the screen right away. New sending unit, cleaned the plugged screen, oil change, and $250 fixed the problem. Truck has 110,000 miles, and it sounds like all are going to do this. Good luck.

I have a 2008 GMC Sierra Denali with the 6.2l... I have had similar issues where rather suddenly I would be running at about 22-25psi oil pressure at 70mph... At first I thought there was an issue with the oil, as, after a full oil change including filter would put everything back to normal... Well, this time it happened with only 4k miles on the oil... Decided to only change the spin on oil filter... Well, as figures, oil pressure went right back to normal. These tiny spin-on oil filters appear to be really cr*ppy!!! Waging a guess, they are collapsing over time... Definitely recommend trying a quick-filter only swap to see if any of these pressure problems we see are related to these sin-on filters. I've tried various brands (NEVER Fram), but have typically had the best luck with ACDelco filters in lasting the longest... This time not so, but thinking about installing a remote-oil filter kit with a MUCH bigger filter... I typically run 8.5k to 10k miles, always mobile 1 synthetic... I even have had my oil analyzed by Blackstone labs at 10k... Oil looked beyond perfect, it passed with new spec... Virtually no contaminants at all... And that was at 187k on the engine...

had same problem 2007 chevy surburban. no oil pressure. changed sensor no change. checked input voltage and gauge circuit all ok. changed oil filter(some one put on no name one) fixed problem.( I always use mobil 1 filters) great oil pressure now. hope this will help someone else

the problems you are experiencing could be related to the o ring on the siphon tube going to the oil pump. An $8 part can cause you a lot of headache as I have found out twice now.

I have a 2007 Suburban with LC9 engine 8th digit #3. Uses oil like crazy, 165,000 stuck AFM lifter.I replaced that one lifter (yes just that one $$) and everything is fine, 180,000 still using oil like crazy, Starting to blue/white smoke on start up. Low oil pressure alarm comes on then goes to 'Shut off engine alarm" then goes away... back and forth while driving. I flush engine and change engine oil and install new Bosch oil filter then I changed out the oil pressure switch and looked at the screen underneath the sensor and it didn't look bad but cleaned it anyway. Dumped 1/2 quart of accumulated oil out the intake manifold UGH, another issue !!! Started truck and instantly I have 60 pounds of pressure. And it didnt smoke on start up (remember the oil in manifold) Purr's like a kitten.Take it for a test drive and after 15 minutes pressure begins to slowly drop until same alarms come on. Next I changed the oil pump and pick-up tube o-ring and everything looks good, purr's like a kitten until I drive it and still does the same thing no oil pressure shut off engine. I was really hoping to get more miles out of this before engine replacement. And if I do should I replace with equal or upgrade to different engine. What do i do next? Cam and lifters? New engine? Any help would be appreciated, Thanks in advance !!

I have a 2007 tahoe ltz 5.3. Saturday cel came on said oil senior high pressure. Stared it up oil pressure was at 80 let it idle went to 0 pressure. Drove it 1 mile checked oi and llooked it over then drove home 25 miles gages never moved from 0 pressure. No ticking no sound from motor at all. So today had oil changed new filter still 0 pressure. Checked the code voltage high and low on abs , oil sensor and water sensor cleared them. Right back on. Reset battery started it up oil pressure went to 80 for 30 seconds then back to 0 psi. And ideas that you all for your time.

These engines have oil pressure problems for sure (aka) small block GM motors. But don't remove the small oil filter under the oil sending unit. It does serve a purpose. On engines that use lifters to cut out half the cylinders during light driving cycles this filter is used to keep small particles out of the passages. If you remove it then your spredding these particles through the lifters and solenoids that control them. There is another problem with these motors that I have repair with great sucess. Email me Mr2tyt1@gmail.com I can help

I had a similar problem with oil pressure being low. I had the Chevy dealership, replace oil sensor and screen. Two months later same problem. Decide to change oil myself. Found that the dealership used acdelco filter. Got a bosch filter at O'Reily s for $8.00. Oil pressure around 40 driving, and 30+ at idle. Seems to have fixed problem.

No pressure turn off engine on my 2007 tahoe 5.3 l v8, was overdue for oil change, went an bought ac delco oil filter changed it and knock on wood, I got oil pressure again! Hope that was it!!!

This has been a recurring problem with my 2007 Suburban 5.3L. The first time it happened, I changed my oil filter and did not see the problem for 1700 miles, then it was back. So I changed the oil and filter and it seemed that the problem was solved. I cut open the old filter and it was covered with a black substance - seemed like maybe a carbon buildup. I think this is what happens, not filters collapsing. I'm guessing it's related to the AFM. Anyway, changing oil every 5000 miles or so, no oil pressure issues for 20,000 miles. Now it seems to be back. Happened about 1000 miles ago, had the oil and filter changed and back to normal. Now after 1000 miles it happened again. I changed the filter tonight and it improved, but the pressure isn't as high as it should be. I'm going to try the sensor screen next.

I would drop the oil pan and replace the o ring on the oil pump siphon tube. I've had a couple a few like this .

I sort of have the same problem but different... I have a 1999 GMC 5.3. With 250 k miles. Give or take 10 miles... I don't know exactly since the odometer only come on occasionally.. My daughter ( the offspring) was driving it today and it just died. I went to pick it up and it had low oil pressure and sort of knocks (not a tap). It starts and has power but rattles knocks . No water in the oil and vise versa... I was told about the oil screen problem but was not sure if the truck has the right symptoms .. I use the truck to haul steel and really don't want to get rid of it but I don't want to throw money away..:. And yes I know I got my monies worth out of the old girl but I still feel like we can work things out... Love Always Willie

Ok let me throw a twist on this. Oil pressure gauge never moves off 35 - 40psi but the alarm comes on saying low oil pressure shut engine down now..... Turn the blinker on and the alarm goes away until next time. This happen when coming to a stop or during heavy drive times.

I fix this issue almost once a month now on countless ls based gm motors, i will try to give symptoms as best i can so anyone can try to tell if this is the issue you are having and i will let you know how to fix the problem. 9 out of 10 vehicles i fix with this issue will not show signs of failure but all have same problems and symptoms and if go unresolved will ultimately cost you an engine. SYMPTOMS: first start oil pressure is normal and slowly drops until shut down warning. sometimes will run a long while without dropping , ive seen some that only drop once vehicle is ran at full throttle. Problem: the oil pump in these engines have a pressure relief valve that dumps oil back into pan, in most cases the valve sticks open and is bleeding off oil pressure into the pan, and a lot of times the engine still runs nice and quiet mainly cause its got plenty of oil volume to flow through the engine just no pressure. TO Fix: Replace OIL PUMP, the pressure relief valve is made into the pump and is not changeable. I hope this may help somebody out there, good luck have any questions feel free to send me a email dsmizzledks@gmail.com

I appreciate all of the info here. Not sure "yet" if one of these will help my case. I have a 2005 Yukon XL 1500, 203K miles. Been a good vehicle. My oil pressure sensor came on for about the last 3 months... started out "monthly", oil was full. Oil is changed regularly. Now it is coming on just about every time I drive. It will start out at about 37lbs in the city driving, going down to about 10lbs or lower at red lights. On interstates, it will go up to about 57lbs. I did have a tap start shortly before this situation started. It doesn't always tap. Replaced the Oil Pressure Sensor. Did not unplug the battery afterwards cause wasn't sure if it needed to be on pre-2007 models. Don't think my husband messed with the filter that is under the oil sending unit, if it has one? If anyone has dealt with a similar year and their problem was fixed, I would appreciate your input. I have been driving it on long trips out of state, so far it has gotten me where I am going.... Thanks!

One more thing, today, I stopped the Yukon and got out to unload something, and it shut off because of the low oil pressure. It acted like it was running ragged when I got out, but because it was about to shut off. It did crank right up again.

We changed the oil pressure sensor and the filter under it and it's still doing it. So is the o ring good to start with?

That is where I would start next.

Whomeveer says the little screen filter under the oil sender dosent do anything has no idea what they are telling you. It is a vital part of the oil system especially since the change to the engine in 2007. Not a smart plan to remove it.

Here is where my 2005 Yukon XL stands today. We have changed the oil pressure sensor and cleaned the throttle body. At first I thought we had success with the throttle body cleaning as we did this about 4 months after replacing the sensor. The oil pressure is still dropping down to 5 lbs or less when I first drive and stop at a few lights. It has shut off once or twice. After warming it up, say getting on the interstate for 15 minutes or so, I generally don't have the drop after that. Hubby has now decided to replace the throttle body. Any thoughts on the O ring that is talked about here... where is it located? Thanks.

There is an issue with the camshaft thrust plate seal failing. Pressure is usally good until warm then pressure drops at idle. The seal built in the back of the plate flattens out allowing oil to bleed by.

The o ring is on the siphon tube of the oil pump pick up. You will have to drop the oil pan, take out a few other bolts, and wham you're there. O ring is about 8 bucks and is a common problem with these engines. Oil pan gasket is about 40. Do not try to reuse the old gasket as it WILL leak.

I work for a chevy dealer in parts Dept. I have the same problem. In the morning low pressure light come on and pressure to 0 but later after 10 min running it stays at 38 t0 40..The recommend me to flush the engine to clean the gums .use 5/20 in the winter. From 2007 an up they use filter at the sending unit.

I would only use oil that is recommended for these engines especially with active fuel management. The lifters in them are not cheap and getting to them are another issue. Use a good oil and these engines will last. I've got one with over 300 thousand on it using Mobile one. The only time I had issues is when I let a friend borrow it and they put the Walmart oil in it. They brought it to me with low oil pressure and I went to people I know and trust and found that these motors are infamous for the o ring on the siphon tube going bad and not sealing up.

Then the same thing happened to my 08 with AFM. Changed out o ring in both cases and both run fine to this day.

I've found that my problem was just a lot of junk from a fresh rebuild on a block that probably wasn't cleaned all that thoroughly. New oil pump, new O ring on the pick up tube, fresh bearings, rings, lifters, NEVER EVER used a Fram filter in my life. Best first pass filtration in the Industry. Drops to near the bottom on subsequent passes. So unless you're changing your oil filter at every stoplight, buy a good one. WIX is probably the number 1 filter available. Personally, I use what came on it OEM. AC Delco. Have used Valvoline from day one. For almost 35 years now it's been Valvoline. Conventional until it's broke in and them switch to Max Life. My problem was caused by plugged up filters. Problem gradually went away with routine oil changes. Now when the pressure fluctuates even a little bit, I know it's time to change my oil.

I am having similar issue. I have already changed the sending unit , the filter underneath, ive flushed the oil added new oil and performance filter and still 0 pressure. Im lost!!

Thanks to all, for helpful info. I'll update where we stand now. Hubby is an old school mechanic, changes oil on time. My GMC Yukon XL is a 2005. I think someone here said there isn't a filter below sending unit before 2007? He has replaced the oil sending unit, and then months later cleaned the throttle body (he did not unplug or move butterfly) After a day or so, it gave warning signals. Then he decided to replace the throttle body. So far, 4 days later, no warning light. I think it is too early to tell. The RPM still idles at 600, and oil pressure drops to about 10, instead of 5 or less. Previously, if I drove about 5 miles and stopped at a couple of lights, generally the second traffic light would be when it would sound the warning. Altho in the last few weeks, I would occasionally get the alarm when I cranked up. I have been driving it primarily on long trips (1K roundtrip each month). Once I get on an interstate, make stops along the way, it doesn't ever have the warning occur. Hubby has been reluctant to replace the O ring and all of that. Said it would cost him (oh, me) $300, and could open up new problems since it is getting older. We are planning to sell it soon as I am looking for another newer Yukon XL. We want to get this fixed before selling it. I will update in a week or so as to the outcome of replacing the throttle body, before moving to the O ring etc.

I have an 05 Silverado 5.3 4x4 and have the same problem. So far I've removed the oil pan and cleaned out all the gunk, removed the oil siphon tube cleaned out the screen and changeg the o-ring, replaced the oil pump, changed out the oil sending unit, I didn't see the filter screen under the sending unit and the dealership verified this year model doesn't have one, i've also removed the valve covers and cleaned out all the gunk and made sure the drain back holes weren't clogged AND I've also changed the oil and filter numerous times and have even used sea foam engine flush but NOTHING has worked. I just bought an oil pressure test kit from Harbor Freight and my luck it didn't come with the right size fitting that will screw into where the sending unit mounts. As soon as I find the right size adaptor that will be my next step before an engine rebuild.

Has anyone ever tried a high volume oil pump to correct low oil pressure on one of these GM engines?

IF your problem is: Your oil pressure drops off after engine warms or it drops off and when you stop the engine and then restart it and pressure goes back to 40 for a few seconds and then drops to near zero again triggering indicators AND (important) when this happens there is NO additional noise from the engine....You have changed oil filters etc.. like religion..you most likely(no guarantee) have a clogged wire mesh filter UNDER the oil pressure sending unit behind the intake manifold on the back of the engine. I see these frequently. Its that simple on these engines folks. They do it all the time. I recommend going to your favorite mechanic and asking him to do this for you but if you are a DYI kinda person..do this to fix it. Start at the auto parts and buying a new manifold gasket set. I see people try to do this without removing the stuff on the front of the engine, trust me, do it!!! Finish in 1/3 the time doing it like this...Start by researching internet and get instructions for removing the Alternator and possibly loosening the AC brackets. (depends on engine and really only if it impedes removal of the intake manifold) How to remove the intake manifold bolts and fuel line. Your goal is to remove the intake manifold from your engine. NOTE:: If you are Houdini you may be able to remove the sensor without removing the intake manifold. Take a look first. The sensor requires a special socket to remove it because of the way it is made in some case socket is also available at the auto parts. Be careful with the sensor most likely it is working OK. Remove the sensor. Now take a long wood screw (3-4") and screw it down into the hold where the sensor screws in the block (screw it down into the wire mesh screen below the sensor) and then grab the screw with pliers and remove it from the block with the screen screwed on to it. Voila.. the problem is right there on that screw. Change to a new sensor? Up to you. Reassemble without that stupid screen...Good Luck.

Hi Mesquite Mike, sounds like you and I are on the same page. My husband the mechanic (by trade too) has done almost everything but the oil pressure test kit or doing it manually?.... In the meantime, I have a fix for the problem.... just bought a 2011 YukonXL Denali. I may have bought bigger problems down the road with all of the gadgetry! lol But I do want to get to the bottom of the problem on my 2005 YukonXL before I sell it. Let me know how things turn out. Thanks!

Same issue here as well. Changed oil pressure sensor, screen filter under sensor, Wix oil filter with high mileage Castrol. 08 chevy 5.3 has 170k miles and this is the second time this has done this. Planning on dropping the pan tomorrow and checking sump, o ring...etc...last resort will be full coverage, trusty helmet and a nice big oak tree at 30mph.

TexasRedbud, to be honest I didn't think to ask if there was one available for this engine. I can see how that might temporarily fix my issue but eventually I'll have to bite the bullet and change out the engine.

So I was finally able to hook up the oil pressure test gage and verify that at cold start up my engine oil pressure will rise to about 25psi and once my engine temp climbs to approx 200 the oil pressure has dropped to ZERO! Pressure will rise with engine RPM but it always returns to Zero when RPMs drop. I found a rebuilt long block (LM7) for just under $2K with a 3 year warranty and free shipping at engineguy.com On a good note, I did get over 200K miles on this truck with no other major problems so I can't complain all that much. Good luck to everyone!

That might be the only fix for my 2005, with the exception that I have the newer 2011 now (it was *only* a $30K fix!!!). I think husband/mechanic will put a new oil pump on the 2005.... did you try that? Or has anyone done so and it made a difference?

I've got the same freaking problem with the lifter tapping. Oil pressure sensor engine code occurred, whom tells me the sensor is bad and that filter may be clogged, which is why the lifter is tapping intermittently. After using engine flush right before the oil change, changing the oil and filter, the tapping only occurred two times for about 2 min each. Drove yesterday and no tapping at all. Tells me something is clogged with a bad oil pressure sensor. Sitting at Chevy right now getting the sensor changed. Hopefully, that's it, if not the next part will be that damn oring. If that doesn't work, that tells me the oil pump going, but highly unlikely that's the problem right now..

I sold mine after all the extra money spent. I couldn't deal with the issues anymore.

Fixed my problem for $2K, new engine runs like a champ

I "knew" there was a cheaper fix than buying another Yukon!!! lol I still have my 2005 and will still tune in to this page to see if anyone fixes theirs, short of a new(er) engine. But I am enjoying my newer one. Haven't made the first payment yet.....

Paul, one of my lifters on my 2005 is tapping about once a month. I will drive it around the neighborhood in the next week or so to see if it is still acting with the oil pressure drop etc. Since I bought another, it has been sitting. But it has been an excellent vehicle and everything still works great even the a/c. Only had to replace a couple parts on the a/c (resistor and actuator I believe) It doesn't appear that anyone has really fixed their oil pressure problems here other than replacing the motor?

I have on 05 Silverado with 270k on the motor...lately at start up I have zero oil pressure with the annoying ding ding ding going off...after rpm are increased oil pressure rises to about 40. I have already changed out the oil pressure sensor and new oil pump. I am buying a new sensor and removing the screen...hoping this fixes the problem...although I have severe tapping occurring from lifters too on drivers side...maybe time to remove valve covers and clean tappet guides.

Similar problem. 05 Sierra with 5.3l 220k miles. Pressure never gets over 40 PSI and most of the time the low pressure is 20, even after warm up. One of my symptoms that puzzles me is that the gauge ( a mechanical one for now) bounces around. Another that puzzles me, if I pick up the RPM's, I can get 40 PSI, but once the lifter starts ticking, the 40 PSI will not pump up the lifter. Based on my past experience, it should. At this point, my plan is to drop the pan, check rod bearing clearances, replace oil pump, and pickup tube o-ring. While this plan seems sound, I have seen several comments here about new oil pumps ( and o-rings I guess ) have not fixed the problem. Maybe I do have a failed lifter, but if so, why will 40 psi at startup quite the lifter, but 40 psi after warm up not do the same thing?

oil viscosity changes as temp goes up...IE: 10W40 (over the temp range) the pump flow changes dramatically at temp also the thicker oil slows at RPM and the combination of the rocker hitting that lifter faster with RPM doesn't allow it to pump up. In your case its back to the pump for me because of what you said abut the guage..

I have a 2005 Tahoe with a 5.3L. It has the lifter ticking when first started and normal oil pressure, The ticking keep s going for about 5 to 10 miles until it warms up. During this time the oil pressure gauge never goes above half way. After the motor gets good and hot the lifter tic goes away and the oil gauge then goes above half way and starts to move with the engine RPM, as it should. I tried an engine flush and marvel mystery oil but it doesn't seem to have made any difference. The truck has great power and acceleration. I don't believe its rockers or push rods because the noise goes away. But after the ticking stops and if I pull up to a store and let it idle while I run in, when I come out it is ticking again, but stops as soon as I start driving again for about 20-30 secs.. I have noticed that during the time after starting it and driving while its ticking, if I come to a red light I have seen the pressure drop to the warning lvl. but that has happened only a few times. Any help with this issue would be greatly appreciated.

I had the same problem with my truck. It is a 2007 GMC Sierra with a 5.3. Try the screen under the sending unit. You may have to remove the intake to get to it but under the sending unit is a screen that if it gets stopped up will not allow the sending unit to read correctly. Also try flushing the engine when changing your oil to remove a lot of the sludge if your engine has a lot of miles. If this doesn't work try the oil pump.

i have a problem with 07 chevy suburban 5.3l 180k..oil pressure gauge stopped working on friday..called a mechanic friend..asked him what to do..if possible was i able to drive in town(live in a small town)..vehicle was not pinging..ticking.smoking..overheating...he said yes just don't drive to far and if it starts pinging stop immediately..drove for a couple of days around town..looked up what might be wrong,,oil pressure switch/sender..went to o'rielly;s and picked up part and socket to remove it..drove 35 miles in vehicle to pick up part..changed yesterday...real bitch to change...got everything put together..disconnected battery to reset computer..started vehicle and oil pressure gauge still didn't work and oil pressurelow stop engine light came on...don't know what to do next ???

I had this problem on my 2008 Silverado at about 105,000 miles and this thread really got me going in the right direction. However, no one is mentioning the fix I did that was recommended to me by a friend who is a Chevy parts dealer and sees this problem a lot. My symptom was as others have described. Shortly after startup, the oil pressure gauge drops to near zero, then bounces back up again and displays the message to stop the engine.. My truck was running fine in all other respects so I drove it home from the mountains, watched the oil pressure and it was stable for the several hour drive home. I never saw the message at highway speeds. When I got home, I saw the problem several times shortly after starting the engine, within a few blocks. My friend said it is probably a problem with the screen. However, he said there are other screens on the oil lifter assembly and that should be replaced along with a new oil pressure sensor. I have done that and that seems to have completely solved the problem. The screen itself is not user serviceable. There is no part number for this screen. Just popping it out seems like a bad idea. To get at it, you need to remove the intake manifold. I had never done this before but it wasn't difficult. It was just time consuming because of all the connectors and lines you need to take off as well as removing the alternator. Underneath the intake manifold is the Oil Lifter assembly. The oil sensor attaches to this assembly. Once the intake manifold is removed, the oil lifter assembly is really easy to remove and replace. There are no serviceable parts on the oil lifter assembly, including that screen (except for the gasket that can be re-used, but comes with the assembly). I examined the screen on the old assembly and honestly it didn't look too bad. So that makes me think it's not as simple as others have indicated. The parts list is as follows: 1) New Oil Lifter Assembly 2) New Oil Pressure Gauge 3) New gasket set for intake manifold (old ones can't be re-used) I am really glad I did the whole job as described, because removing the intake manifold is not really something I want to do again. So while you're in there, you might as well put new parts in. I hope this helps some else.

Here is an update on my 2005 GMC YukonXL oil pressure problem. As stated above, my husband replaced the oil pressure sensor (according to some here and schematics I believe, there is no filter screen under it in the 2005). He also replaced the throttle body a month or so later. After doing all of this we still had the problem of the oil pressure dropping. He has now replaced the oil pump with a high volume oil pump and O ring. He said there were 3 different color/size O rings and it appeared that the orange'ish colored one was the one he removed and replaced with the same color. He said the old O ring was rather hard. After doing this work, I am happy to report that the oil pressure is 60-65. It appears to be fixed now. I bought a 2011 and am not driving the 2005 enough to say that there are no further problems but it has been running well when it is driven. I hope that this helps others with the same problem. In and older model with 200K, I think I would start with the oil pump and O ring first to see if it fixes your problem.

Update on the status of the fix after replacing oil lifter assembly, oil pressure sensor and oil change on my Chevy Solvetado 2008 with 105,000 miles on it. The problem seems to have been fixed completely. Did a round trip to mountains since fix and been driving around town. Pressure gauge is behaving much better. It never drops to as low as I was seeing and is showing higher than 40 under acceleration. I wonder what this oil lifter assembly does? If it is failing, I wonder if it doesnt move oil around lile it should? Maybe there really was a pressure problem? Of course it could have been the sensor failing as well. I am leaning towards the screen not really being the problem in my case. It really didn't look dirty or clogged. Chris

Upon further reflection, I am certain the only problem I had was a flakey oil pressure sending unit.

2007 Chevy Silverado K1500. I had the same problem; fluctuation oil pressure and would drop to zero and tell me to shut the engine down. The oil level was good, and was still at 25% oil life with about 6 months since the last change. Someone said that the oil filter may be clogged or have sludge in it. I went and got my oil changed and the problem has since gone away. Hope this helps.

My problem ended up being the oil pump and/or O ring. My husband is an old school mechanic whom changed my oil meticulously on time.

Just seen this we just bought a 08 Suburban LTZ with the 5.3 160k... The check engine light was on when i test drove it oil pressure seemed ok though well they told me they ran the codes and it was a evap code and there repair shop would fix it no problem so i bought this thing and being a ex ase tech i decided to run the code my self when i got home it was just bothering me... So of course it was on for low oil pressure so i called there shop which told me they cant get it in for another week so im waiting on that i decided to just go get the filter and spending unit and change the oil at the same time with good oil and a good filter really wasnt bad to change just removed the pcv hose and fuel line got right to it... Well after pulling the sending unit i found some one has already removed the screen so i went ahead and installed the new pressure sender and changed the oil... Well at start up has around 60psi and slowly as the temp rises dropes to about 5 to 10psi on a mechanical gauge... I do know the pressure stays around 40psi while driving but as soon as you stop its down low and im prety sure i can hear some lower end noise every now and then once warm and idling for a little bit...Sure there gana try to screw me on this also seeing as it was bought as-is... Gana see what they will do for me since they said theyvwould fix the problem the light was on for then might try a new oil pump next if they dont help...

What if you had the ac/heater blower motor repaired under neath the dash and right after that you get the "low oil pressure turn off engine" light on. Can a oil gauge malfunction be a possibility and related to the blower repair? Is it possible that a wire was knocked loose or something to that nature? I'm having the same problem and it happened right after the blower repair. I've already changed the sensor switch and I still have the same reading on the dash. Any insight would be very helpful. Thanks.

I had a Similar oil pressure problem. We bought a 2008 Suburban 1500 5.3 AFM (active fuel management), 4 wheel drive, with 183k this past December from a private seller; we met at a local Walgreens (mistake #1), and then I discovered a few days later that I had oil pressure problems. The first problem was that when the temperature dropped below 10 degrees (I live in Minnesota) the pressure would drop to 0 when I would start the vehicle in the morning. In order to keep the pressure up I would need to nurse the rpm until the engine warmed up a little, then the psi would stay above 20. The second problem was that I could not get the pressure past 40 psi no mater how high I ran the rpm, that is until the motor was completely hot. I would see the pressure slowly rise while driving on the freeway until it was finally up to 55 psi when the rpm was above 2500. This would usually take 20 minutes. At normal cruising speed the psi would run around 38. I also had a pretty loud lifter until the motor was heated completely and then it would quite down. Steps followed to fix the problem: 1) Researched on the internet (mistake #2). 2) Purchased an oil pressure sensor and AFM filter srceen. 3) Researched Alldata and realized my problem wasn't likely to be caused by the screen or oil pressure sensor (AFM worked fine). 4) Replaced screen and sensor anyway since I had them. 5) More research (problem not solved by step 4). 6) Purchased pickup tube o-ring and oil pan gasket and assembled tools (mistake #3). 7) Pulled the pan then realize that I never wanted to do that again so I went to the local dealer and purchesed a AFM oil pressure relief valve (located in the oil pan) for $13. 8) Replaced the o-ring, AFM valve, reinstalled the pan replaced the oil filter, added oil, started the engine (before re-installing the front differential) and watched the gauge go right to 60 psi (whew). The oil pressure is now acting the way I would expect it to; starts out high, drops a little as the engine heats up, fluctuates with rpm. I still get a little lifter noise at first but it quiets down after a couple of minutes. Lessons learned: 1) When buying a used GM truck (or any vehicle), always be the first to start the vehicle in the morning (ref mistake #1). The Suburban was completely heated when we test drove it so everything seemed great. I don't know if the seller purposely deceived us, I like to think not, but I will never buy a used vehicle again unless I get the chance to cold start it. 2) Research on the internet is great (ref mistake #2) but be careful, there are a lot of good intentions and a lot of bad advice. If an AFM screen is getting plugged by sludge & crud, it's doing its job, don't delete it from the system; there must be some other problem, I didn't have any sludge in my screen filter or pan. 3) Do the job once. I'm not sure if replacing the AFM valve helped but for $13 it didn't hurt and I will never need to pull the pan for this issue again (at least not on the vehicle). 4) Have the proper tools (ref mistake #3). If you decide to do this yourself and you have a 4 wheel drive, buy/rent a transmission jack or buy a transmission jack adapter for your floor jack. I used an ATV jack to drop and install the differential and it made the job so much harder. Some people lay on their back and muscle the differential out and back into place but I'm past that age. I hope my experience helps.

So i have solved my Lifter noise / oil pressure problem. I installed a new oil pump, but the old one looked fine and was not the issue. I am convinced the O-ring on the oil pump pick up tube was allowing air to be pulled into the oil system. The oil/air mixture would have low viscosity that would allow the lifters to leak down and rattle after the engine was warm. This type of air leak on the oil suction tube could cause all types of problems.

Maybe mine is a slightly different problem because I replaced the sending unit and the intermittent low oil pressure issue seemed to disappear. But then returned. Mine APPEARS to be electronic. I say that because if goes from normal to zero in a fraction of a second then back to normal in a fraction of a second. The needle jumps. If the pressure was indeed zero and building back up the needle movement would be slower. As far as clogged screens, I cannot see how the needle would not go low and remain low.

Could be the step motor. I know there was a problem with 2006 and older. You can buy them and replace yourself or send the instrument cluster in for repair. Clouis

Yeah I soldiered new ones in my 03 couple years ago. They went out one by one. This one is acting differently than each of those that went out but I will keep that on my list of potential things. Thanks

So my issue is that at various times, or not at all, my oil pressure gauge will go to near 0 and the oil light comes on with the alarm bell ringing. I can run this for 1 mile or 10 before the problem starts and when it does it stays in this condition until it is shut down. No engine noise, no tappets or anything, just that ringing...or not. Oil and filter just changed and no change-- it's being suggested that I replace the engine...seems a rather strong reaction to this problem, or is it?

Your problem sounds like the one I had on my 2005 Yukon XL. We changed the oil pressure sensor and cleaned the throttle body, working through possible fixes, before finally changing the O Ring. I didn't have anymore problems after that, before I sold it a month or so later. Bottom line, the 3rd try may have fixed it. So I would suggest starting with the O Ring. (see my earlier posts above)

Update: Mechanic hubby put a high volume oil pump and also a new O ring on the pickup tube. After that, the pressure was always high, I think around 65 lbs. I also had a lifter(s) rattle about once a month. After replacing the pump and O ring I didn't have any further problems for the month or so that I kept it. Primarily my oil pressure would drop down to less than 5 lbs after I drove it a mile and then I would spend my time at red lights with my foot on the brake revving the engine to keep it from about shutting off.

2005 Suburban STARTS at 0 pressure will rise when driven but idles at about 10. Changed oil and recently had pan gasket and that o- ring done so going to try sensor next?

Hi Sin_T_Ter. I am basically having the exact same symptoms and same year truck. What fixed it for you? I am hoping you say it was a faulty stepper motor in the gauge.

Mine went back to normal after changing the oil 3 or 4 times in a month and using only good ACDelco filters. Also put Lucas in it. I think it was just sludged up.

First off this problem is a gold mine for chev and gmc maintenance departments. Drivers of these 5.3 engines experience the problem and the majority bring it to our dealers and they tell us the "book" says it takes 2.5 hours to replace plus parts. Our son took his to the dealer and they charged him over $500 I was fishing with a retired gym mechanic and he told me he could change the gauge in 15 minutes. I got mine done by a non gm shop and it cost me $100 for labor and parts. After I replaced it I had problems again and he told me over the phone to go to an auto parts store and get an engine oil flush and put it in 5 minutes in a hot running engine before they drop the oil out. I went to Napa and got their brand plus a wix gold filter and changed the oil and it has been perfect since. I'm going to do it at my next oil change as well . I have 158k miles on my truck. When you google a mechanic that tells you how to do it he got it done in 17 minutes. This is a flat out rip off by gm dealer repair departments.

I ended up putting a mechanical gauge in and ran it into the cab. as many times as the motor lost pressure and wasnt making any noise i was sure it was either the gauge or pressure sensor. it finally tanked and mechanical gauge stayed up. so i just drove home and ordered a sending unit. that damn ding ding ding drove me nuts for the 20 min drive home.

Will the screen Clog cause valves to tick?

It could but it's important to keep it in. It protects the small passages from getting clogged. It's purpose is for the management system that cuts off 4 cylinders during light throttle

I have been dealing with the low oil pressure on my 08 silverado for many months. Replaced the sending unit and screen didn't work ran eng cleaner didn't work tried oil additives didn't work tried turning volume up on radio didn't work what did work and I believe this is the correct fix after reading many answers drop the oil pan and replace the oil pump pickup tube o ring. It was hard as a rock and broke apart when I touched it.Oil pump was good. Oil pressure is now 40 psi at idle 60 psi at hwy speeds.

My 2012 5.3L Silverado with 130k had the exact same issue described on this thread. This is what happened to me and how it was resolved. I got the low oil pressure signal while at highway speed, stopped, checked oil(Full), no engine clanking so I carefully limped it home, stopping several times when the pressure returned to zero. It would jump to normal after stopping for a while. I could get about 4 miles out of it. I changed the oil pressure sender and screen at home. (Its hard to get at, but it can be done easily with a proper set of tools including a oil pressure socket) Ran fine for about a week, then the low oil pressure returned and worse than ever. I foolishly took it to a dealer to have the 'experts' check it out. They called me back later. They had attached a mechanical gauge at the top of the engine and also at the oil filter. They confirmed that the oil pressure at the top of the engine was sliding to zero, but the bottom gauge was normal. They said "we're not sure, but some sort of pressed fitting rotated in your engine and YOU NEED A NEW ENGINE". I luckily called BS on that and told them I wanted to know what "pressed fitting rotated". They couldn't tell me even after I talked to the GM district manager. It all sounded fishy so I picked the truck up and drove it home. Had no problem with the oil pressure in about 20 miles. I started talking and asking around using the internet a lot. I got some things to try. This is what has cured the problem for me: - I flushed the engine with a 5 minute crankcase flush, I think it was called 'KW 5 minute flush' - Full oil change using Mobil 1 full-synthetic 5W-30 - A Mobil 1 oil filter, a M1-212. This is a larger filter than is specified. The advice to use a larger filter came directly from a GM technical bulletin. I have had no problems since this was done about 2000 miles ago. I believe the problem is solved. An interesting point is that I had no more problems after picking up the truck at the dealer. When I arrived home, I noticed that they had replaced my Fram oil filter with a larger ACDelco filter, A PF63E. I believe the low oil pressure issue is related to the size/capacity of the oil filter. Don't ask me how, but GM recommends a larger oil filter in these vehicles now. Also, I was using Valvolene Max-Life 5W-30 synthetic blend oil. I don't believe this is an approved "Dexos -1" oil anymore, it was when I started using it, but it is not anymore. I am switching to Mobil 1 full synthetic. Another small interesting piece of information is that before all this my fuel mileage was dropping from about 16.5 mpg to 15.2 mpg's. After all this fiasco, and changing the TRANSMISSION FLUID, my mileage instantly went back up to 16.5mpg's and is still climbing! The AFM switches to V4 mode much more often. So here is my advice if you are experiencing low oil pressure: Replace oil sending unit and screen, Flush, change to full synthetic oil and most importantly, use a PF-63E oil filter or equivalent. I hope this post is of some help.

Have not read any issues similar to mine but will share for anyone that might recognize the symptoms. 05 Silverado 5.3 Smoked (past tense) horribly when first starting with new pressure sensor installed. No screen in place under the sensor. Reinstalled the faulty sensor -- no smoke! Tried another new sensor with same results. After probably 4-5 times trying to use a sensor and referring to several mehanics I finally Installed a mechanical oil pressure gauge ,but the truck lost all pressure at stop signs and would barely cripple across the street before building enough pressure to stop rattling. Took off the tube to the mechanical oil gauge (@ the original location of the oil pressure sensor) and installed a short piece of iron pipe with a cap on top. Runs great. No smoke. No rattle. Also, have no idea what the oil pressure is. My truck has 285k and runs strong. In a way, I hope this does not encourage anyone to copy my approach, because I'm sure this is the worst possible action a person could take but it produced miracles for me and now after about 5 months later still drives great.

Just in case some people are scared of a rebuild looming... I have a 09 Silv NBS 5.3L. Motor has burned oil since day one. I do oil changes every 17,000 - 23,000 per oil life monitor (crazy i know). I have pulled a 7k lb trailer over 100,000 km of trucks life. Truck has 481,000 km on it currently on original motor and trans (trans oil change every 120,000k). I have the same problem with the oil pressure sensor on and off pressure. It seems to be worse if I do not use Valvoline maxlife for some reason and do not know why. This really limits my choices for oil changes while on the road. I have ran this truck out of oil, started it on fire, ran with percieved no oil pressure for over 6 hours at 80 mph pulling a sled trailer through idaho and montana. Truck still runs fantastic and does not burn any more oil than it did since new. Anyway, I will check this filter again, as I paid someone to change it but problem still persists off and on. Motor is does not make any ticks or knocks so i know it has to be oiling especially since I have been running it like this for a couple years now with out being able to fix the problem. Will run months with out issue and then pressure will drop while driving and return as fast as it dropped. Would there be any other cause for this besides the sensor filter?

I had an 04 GMC 1500 with 5.3 in 09. I bought it with about 45K on it and every thing was great. After about 6 years and 75 K I noticed the ail pressure started to drop. I was running Castrol Syn 10w30. I don't know what kind of oil was originally used. The oil pressure would go down to about 20 psi under load. Some one told me to pour about 1/2 can of SeaFoam fuel treatment in the crankcase and drive it for about 100 miles. Drain crankcase replace the oil filter. To my surprise the oil pressure came back up. After about 700 to 800 miles the pressure started to drop off. Pulled the filter and it was plugged with like black syrup. It took me about 6 times doing this before the oil pressure stayed up for about 5000 miles. Before I did this I had a lifter ticking and a miss. Cleared this up. I think that the pickup screen was plugged oil consumption good. There was no harm using this chemical.

Did you fix the low oil pressure ? What was the problem. Im having same problem

Ours is similar but I know for a fact it started throwing the "low oil pressure Stop Engine" light after my battery died and I swapped it. Ran perfectly up until then. Got our first really cold weather for the year and the battery died. A couple days later I picked up a new battery and installed it. Immediately we started getting the dinger and lights after driving a short distance. Idles below 600 and we get rattle then too. Shut it off and right back on and it runs perfect for 15 or 20 minutes and does the same thing. Now the blinkers stay on after I return the blinker leaver to center. Sometimes when it starts to act up it turns a blinker on all by itself. Definitely electrical in nature. Is it possible that after losing it's memory due to the battery, it's misreading the fuel/air and trying to change the timing a little which is making the rattle? Oil always changed, Oil full, etc. Started as soon as new battery installed.

Word of warning--I removed the screen as suggested in a previous post due to oil pressure gage showing low oil pressure. Hooked up manual gage which showed good pressure. Replaced sending unit and after the motor ran for a few minutes the pressure dropped again. At this point I discovered the lifter oil filter under the sending unit. I removed it and discover it was clogged with metal fragments (nonmetallic) so I tossed it as several posts suggested. Big mistake! My motor has DOD/AFM. Within 10 miles one of my AFM lifters stuck open and I had to remove a head and replace the lifter. 180k miles. I guess the engineers put that $7 screen there for a reason. GM should recommend that thing be changed at 100k miles.

I have a 08 Chevy Avalanche. i noticed that after i drive for a little bit and the truck got warm. the oil pressure would slowly drop down to 20 sometimes lower. i replaced the oil pressure senser and filter and it still does the same thing. What do i need to do next?

On my '09 Chevy 4wd 1500 Silverado with 144,000 miles. Family light duty use: - 2 years ago low oil pressure alarm when driving. replaced screen/filter under sensor. Plus sensor. Fixed. - Last month, same low oil pressure after driving. Starts around 40psi then drops below 10. - Changed screen/filter under sensor and oil pressure sensor. Worked for one week-- same issue. - Can "baby" the engine and won't get alarm. - Changed oil pump, pickup tube and seal-- same problem. - Changed oil "diveror valvue" at back of oil pan and added the recommended "hat" over it. Same low oil alarm problem. - Changed cam retainer plate with builtin seal to OEM upgraded plate/seal with new bolts. The old seal was "flat" (thought this would fix it). - Still not fixed. Pressure drops to 15 psi at idle. check engine code, but no "bells" or warning for low pressure. The mechanic is now saying I need a different engine. Any other suggestions, before I go the new/used engine route or start pickup shopping?

I had the same problem. I have an engine with DOD/AFM. There is a small screen/filter under the oil pressure sending unit to filter debris from oil going to the lifters. If this is clogged the oil pressure sending unit does not get supply. Cost $7 at dealer. Do not take it out and not replace it. This could lead to collapsed lifter. Replacement of lifter is not simple or inexpensive. After I replaced mine at 180k my oil pressure at idle is 45 psi and 555psi at 1000rpm. I will replace filter every 50K from now on!

NobleMO - I would try changing that screen again even though you just did. Could be defective or maybe there's something in your oil that clogged it quickly. I would change the oil and filter too, but if you made all of those other repairs since it started again, I'm assuming that was done. Did you replace the sending unit? You could either replace it or check the pressure with a mechanical gauge. But replace the screen again regardless.

Sending unit good. Changed oil and filter. Screen is clean. Finally changed lifter and all is good. Oil pressure 45lbs. at idle and 55lbs. at 1k rpm. Gm should issue a bulletin and letter to all owners to change that screen at least at 100k miles. It was the start of my problems and the ultimate solution. By the way, if you check oil pressure with a mechanical gage you are checking it at the same location as with the sending unit (downstream of the screen) and you will get the same results provided the sending unit is good. When you change the screen be sure not to get debris in the oil passage. I use a wet/dry vac. to clean mine out.

My 2010 Silverado 1500 (188k miles, runs terrific). But Oil pressure drops to zero and Indicator saying turn off engine. FIX, put in few ozs Seafoam, drove bout 75 miles, I changed oil and new Bosch oil filter! Now Pressure holding near 40 after few miles of of driving so far. I read online Someone say they change oil and filter that solve their problem. It’s of mine too so far. Good luck everybody

i have a 2000 suburban and i had the same problem. when i came to the holt. my oil pressure dropped, the engine was going out of power, then when applying the pedal it went to normal. i gotten a intake manifold gasket replaced and my o2 sensor downstream replaced. and it fixed my problem. he runs like a baby ;}

I found theres a valve in the oil pan that can go bad. Had the same problem works fine till the oil heats up

willie sounds like lifters need checked

I have a very similar problem. Bought a 2011 avalanche with 75,000 miles. Everything worked good till I hook up our rd trailer to see how it would pull it. When I accelerated hard the oil pressure dropped to 0. Kill it start back 40# pressure. Drive with out trailer still drop when accelerated hard. Changed sender and sender filter. No change same thing. Changed oil pump, and doing on pick up tube. Same problem. I remembered reading a post where a guy said change oil filer that the bypass valve sticks open and very little pressure. I did that. Oil pressure came up to 40 to 45# and would stay there, now 6,000 mile later the same thing again. 40#cold r accelerate the drops to 15 to 20 #. Going to change oil and filter again to see if this fixes it. There is a plug on the lower side of block, does anyone know if this is a oil gammy plug. Want to put in a mechanical gauge

I have a 2000 chevy silverado 1500 5.3. Low oil pressure came on, truck cut off, towed home. Have replaced oil pump, oil pick up tube, sending unit. dropped pan, cleaned everything. Low oil pressure light still come back on and now makes a little tap. Gauge apparently is not working, cause it still doesn't move.

What I am wondering, is the 2.2 GM computer faulty, can it change oil pressure to prefect on start up pressure, then after a bit of driving the computer then kicks down the oil pressure by its self? I hear the oil sending unit does 3 separate functions, that is about all I know. Does the computer control pressure internally to keep the 2.2 GM motor oiled? If it does, that explains a lot about perfect pressure then hardly any pressure til high idle. 12 8 18 RDW

Update on my ‘09 Silverado that had cam retainer plate, oil pump, pickup, screen, and sender changed but still had beep beep low pressure. Using Mobil 1 synthetic and filter brings the pressure up to 18-20 at warmed up idle and 38 psi max. Substituting one bottle of Lucus high mileage treatment to the mobile 1 brings it to 24ish and 42 max. I driven daily and on 1000 mile trips pulling a 16’ cargo trailer- no issues, just lower PSI than my suburban with same engine. I’ll drive till it stops I guess.

Best Answer i have seen a bunch of these truks with this problem and what it iis there is a small screen under the oil pressure switch that gets sludge in it and stops oil from reaching your pressure sensor, remove your oil pressure sensor on rear of intake and take a small pick and pull out the screen and throw it away, reinstall our oil pressure sensor I have already done all this and it reads good when I start it but after warm up starts reading about 20 until rpms are higher then the oil pressure rises

Not the O ring on pick up tube, replaced that, not the screen below OPSU, replaced that, then removed that, on the third OPSU, replaced the oil pump, several oil filters, over $2000 in work and my oil pressure sits about 15-20 unless highway acceleration, then jumps to 30, and back down to about 18. 18 seems to be it's favorite spot. one problem supposedly was oil in the plug that connects the OPSU causing a short, changed that, nope. So, I have seen ALL OF THESE problems listed here and NONE of them are it. Now what? No engine noise at all of any kind, runs great.... is 20 the new normal here or what? The dealer is useless and can't figure it out either.

Have you checked your oil pressure with a manual gage? Maybe it isn't really low. I have a Envoy Denali with 295k miles holding a little over 40psi at idle and 50psi or so at 1000rpm. At one point, several years ago I had to change the sending unit because it was sending a bad signal. Also had to change the stepper motor in the instrument panel for the temp gage, but the on for the oil pressure is the same.

Hello everyone. I'm having what sounds like the same issue as everyone else, except this is the 4th time. I have a 2010 GMC Sierra with 94xxx miles on it. The oil pressure sending unit went bad about 3 years after I bought the truck brand new. Dealership changed it out for a few hundred bucks. A few years later, I got the same "Oil Pressure Low, Stop Engine" light. Dealership wanted nearly $500 so I changed out the part and the screen myself. Ran fine for another handful of years until last October. Same thing again, but I brought it to a new mechanic. They changed the sending unit, screen, oil and filter, along with an oil cleaning treatment and fuel cleaning treatment. I don't think I've put on 2000 miles since then and it's happening again. I'm wondering if there is something else that I should be thinking about getting fixed or looked at that keeps causing the same problem. The truck runs fine after changing the unit and screen but this is getting too flipping expensive to have to fix every year. Any suggestions?

I wrote an article concerning some of the problems dealing with this issue. If you respond to the email address I'll send you the article and provide you with any assistance I can with what has worked in our shop. Rick... mr2tyt1@gmail.com

Changed oil pressure switch and screen underneath, still throwing P0521 code, idling with about 12 lbs. pressure. Read other posts and decided to have the oil changed at a different business. 1 hour and a fresh Valvoline full synthetic oil change with appropriate filter later, idling at 35-38 lbs. pressure. Know who is doing your oil changes and if it sounds too cheap to be true, it is. 2012 Silverado 1500 5.3L w/58,000 miles, oil changed every 5k.

i have 2013 with 5.3 that had oil pressure issues even since i got it, every oil change they tried something different which involved changing the screen and oil press sending unit. at 85,000km they could not keep the low oil pressure check engine light clear and with 1 week left under my warranty they were going to complete internal investigation. a week later i got my truck back with a rebuilt engine claiming the rear cam bearing was shot and the issue even though my oil pressure was still low and reassured me that it was normal and to bring it back when it comes back on. well after one oil change things were ok still and now 1 year after my rebuild and 40% left on my oil life monitor suprise suprise the check engine light is back with constant low oil pressure. i am convinced that they cut corners and did change some of the oring combined with lack of cleaning during the rebuild sludged up my oil to cause the check engine light. They are going to take a look at it but im interested to see what BS they try to feed my next, a good trick i read was to jack up the back of the truck and add oil so that the oil pickup oring is submerged to tell is oil pressure raises then its a bad oring, so i will try that and see but i like the idea of a bigger filter. the bottom line this engine was poorly engineered and some simple fixed in a technical service bulletin could have solved this years ago!

update: took it back with 5000kms on synthetic oil and all they did was change the oil sending unit and screen then claimed it was fixed. when i started up my truck there was no change at after dropping $350. i went back and asked for my old oil sensor back as it was brand new and not the issue and they recommended an oil change with no surprise there! on the way home from the dealer i got PO521 in again.... I ended up doing my own change this time with 10W30 and went with a larger filter and put in some lucas oil treatment for good measure. the oil pressure was a little better which it should be with new oil but still seemed on the low side. after a week the dealership contacted my wondering why i never brought it back and gave them a earfull and offered a free diagnosis. They eneded up having the truck for 2 days and after consulting with GM they claim its "within GM spec" despite on the lower end and would not do anything unless the engine was shot again...

I have a 2007 suburban 5.3L and have been dealing with low oil pressure problems for about 1 year. I believe I have found the answer. Email me Drodriguezchp@msn.com

I have a 2007 Suburban 1500 with the 5.3L engine. It has 309K miles. Engine had problems at 230K with lifter noise before I got the car. It was AFM lifter on #7 cyl. The lifter was replaced and the car ran for another 60K before it happened again. Again the lifter was replaced but this time it ran for only 30K before it went. I got the car and replaced it again but it was only a short while under load before the lifter was ticking again so I took the engine apart, replaced all lifters and the cam. Removed the AFM stuff and had the computer reprogrammed to leave out the AFM crap. The engine did not have oil pressure problems except while in limp mode. Had I known then what I know now, I could have cleared that up immediately by just shutting the car off, clearing the codes and starting it again. (I don't know how, but somehow they manufacture all sorts of problems in limp mode which suddenly disappear if you can get it out of limp mode. If you don't believe me, just leave the throttle body connector off and start the car. It will go into limp mode almost immediately. No power, charging system refuses to charge the battery correctly, multiple codes are thrown, many (even most of them) not related to throttle body issues. Replug the throttle body connector with the engine running and just reset the codes using your trusty reader. Voila! The engine is running as good as gold! All of those problems were due to limp mode, not throttle body stuff. What a con job!) Anyway continuing on. When I started the engine afterwards, it had some initial problems due to things that I had missed, but after those were corrected, it ran fine. I drove it maybe 80 miles trying to get it ready for inspection, but it suddenly began throwing P0521 codes. I checked on that problem on the internet and decided to replace the oil pump - perhaps the o-ring was bad. It was and I replaced it. Now I have good oil pressure. No, wait the oil pressure is dropping and here is that code again! So I switched the oil to O'Reilly's 10W-30 for high mileage engines plus I added a quart of Lucas High Mileage gooo for good measure. Pressure is up a little and the thing almost passes the monitors but fails with the P0521 code now and then but always before I can get it inspected. I took it to a diagnostics place and they charged me $130 to prove that it was not a wiring problem and they also verified the oil pressure. I had been proven right, but still no fix. I read in my investigation that the high volume oil pump was not a good idea because it could cause cavitation in the sump pipe so when I had replaced the oil pump I had purchased a standard replacement. Now I am thinking that this is wrong and I am going to replace the oil pump again with a high volume version for $150. I am also going to buy the cam load plate with new seals to make sure that the leakage is not there. I also plan on purchasing the larger oil filter and if all that raises the oil pressure I will go back to 5W-30 oil. I was never experiencing any lifter rattle or strange engine noises until I put in the Lucas and 10W-30 oil. Since then I have had some lifter noise now and then. So if the new pump works good on the 10W-30, I might go back to 5W-30 - depends on how the engine sounds. BTW I replaced the oil sender with the cam change because I got a new cover for the valley area which does not have the AFM stuff on it. Plus it has no location for the little filter under the sender. I also left off that baffle that hides the sender so I can easily get at the sender unit - piece of cake to replace it now without any special tools. In fact a deep well 6 point 1-1/8" socket (I think it was) works fine. I also found that I could use a 3/8" flare union to insert into the hole for the sender so by using a flare 'T' and adapting to the sender and to a mechanical gauge, I could verify that the readings of the sender were comparable to the gauge. I never was able to catch the pressure change when the code was thrown, but I did capture this data in the picture for one of the P0521 codes. The code was thrown after the car was moving along, slowing down after exiting the freeway where 70 mph speeds were occurring. As the car slowed down, engine rpm dropped below 600 to about 519 for a moment and the code was thrown at 937 secs when the vehicle speed was near 60 mph but the engine rpm dropped so low and the oil pressure dropped too low for that speed. I think that the pressure dropping below 30 psi caused the code. This is absurd! And it is certainly no reason to prevent the vehicle from being inspected! I found out that the code is thrown when for a given temperature, speed and some other parameters, the oil pressure is expected to be within a +/- 7 psi window from some magic number that those scoundrels drew out of a hat! Under certain circumstances, a nearly new engine will exceed those limits IMHO and this is a blasted scam! And GM won't do anything about it although they have known for years what the problem is!!!

To check and see if the Oring is the problem, over fill the engine with about 3 quarts of oil. If the oil pressure comes up it's leaking. happy trails.

I have this problem with my 2011 Silverado 5.3. Changed the oil sensor and filter under it. Worked for 2 miles and dropped off pretty quick.

I went through this problem. Check my post of everything I had to go through in my post, but the short answer is that you need to change the filter ($2,50 from amazon prime) under the oil pressure sensor or clean the old one. I removed mine by screwing a 6mm bolt into the old filter and pulling it out, I simply cleaned it with mineral spirts and compressed air, then replaced it. GM should put this on their 100k mile maintenance schedule.

Check and clean the filter again--at one point on another vehicle I had this problem and found that the filter had clogged again. It took 4 tries to clean things out but things got better each time until it finally worked. I got to the point where I could remove it with my 6mm bolt, clean and reinstall in about 5 min.

It is 90 percent the little filter, throw that dang thing, and always better to put new sensors In to be safe!!

The little oil filter is almost never the real cause of the symptoms in the OP question. The problem has to do with either the oil pump intake o-ring or AFM foul-up or sensor failure. If poor oil has been used, the filter might generate an error code but almost never. The vehicle in limp mode will display low oil pressure on occasion too, which should not be discounted either.

In my experience with a couple of dozen (give or take) vehicles, all but one has been a clogged screen on that little filter. One person I know had the oil pressure sensor replaced and then the oil pump only to find out that this small filter was clogged. It is so easy to clean that I would always make that my first step. The one time I found this not to be the problem turned out to be extremely low oil level. I have seen comments from some who say the filter is not needed so just remove it. Personal experience--someone I am very close to left the filter out, got debris in a lifter and had to replace a collapsed lifter. Not fun on this engine since the head must be removed. I have run one of these motors over 300k and this is the only problem I have had except for a broken exhaust manifold bolt (which seems to be a common problem) and a crank position sensor which I think burned up from the manifold caused by the broken bolt. What ever you do, don't throw that filter away. Gm wouldn't have spent the extra nickel if it wasn't needed!

If your pressure seems normal and fluctuates like that, it is the stepper motor behind the oil pressure reading on the dash. Put the truck in neutral with the (P) brake on. remove the dash bezel, remove the whole cluster, get some stepper motors and replace all of them at the same time since you have the cluster out anyway. You can get a kit off Ebay that has all an instrument gauge kit that has everything you need to do this job. It is not the sending unit, engine flush, oil additive bla bla bla. Don't waste your time. Pay 30 bucks and spend some time on it. There are videos on how to fix it the right way at your house.

I have a 2009 gmc Sierra. I did the afm/dod delete and after that I had real low oil pressure. I did everything that is on this blog and it turned out to be the camshaft pressure plate. Replaced it and I gained 10 psi in oil pressure.

I have a 07 Yukon and 07 GMC 1500 both under 30 psi I removed the oil pan and the oil pick up had come loose that solved the problem on the Yukon now to work on the 1500.

This bad boy comes loose (pump screen tubing). it's like if you're sucking soda with a broken straw. You get lots of air bubbles. Fixed my 07 Yukon 4.8. now I have 40psi or above. Now to try it out on the 07 1500 Sierra.

2007 5.3 Tahoe, 0-80 psi back and forth, would get stuck on 0 psi and the low oil pressure warning light and the annoying ding would sound off! Mechanic replaced the screen and oil sending unit today! Oil pressure back up to around 40-50 psi.

Short answer: acdelco oil filter 12706595 Now the rest of the story: this a $7 filter made for the corvette. I have a 2009 Silverado 5.3 with the dreaded afm. As soon as my truck would get up to temp the pressure would drop out to nothing. I changed out the oil pump, the o-ring, and the oil pressure sending unit (4 times). I finally called my awesome mechanic to see about an engine swap and he told me to try this first. I could not believe it, it totally works. Now my truck starts out at around 45 psi at start up and after it warms up it stays around 40 at 2000rpm and goes down to 20psi at idle. Can drive all day no problems. I don’t know the why or how but for $7 you have to give it a shot! And then spread the word!! Make sure to respond to this so others know it’s real and works.

2012 tahoe when start up oil pressure is at 20 and 40 when driving any suggestions on what causes this low pressure, engine runs fine and doesn't make any noise

I have this same problem happening despite being full of fresh oil. My plan is to try the tips provided, but could this be an oil pump problem?

I have brand new lifters brand new oil pump new oil sending unit it holds a little bit of pressure but it's throwing a code and it's making my truck run like crap any ideas for anybody

After years of trying it all. I believe I finally figured it out. So far it’s working for me. There is an oil pressure relief valve in the oil pan. GM Genuine Parts 12608835 Engine Oil Pressure Relief Valve And GM Genuine Parts 12639759 Engine Oil Pressure Relief Valve Deflector. One is the valve and the other is the deflector to help with consumption. My 5.3 suburban is just around the corner of 300k miles. Hope this finally helps everyone. Let me know. Good luck.

I have a 2011 Sierra 4x4 with 5.3 (LC9). I had the VVT and DOD deleted and at first it would have a constant oil pressure at 40 idle warmed up and it would go up to 60 psi when accelerating. So I have not moved my truck much because now it starts at around 30 psi and slowly loses pressure and goes down to 0 when fully warmed up. I have replaced the oil sender unit with an ADelco one and removed the screen since the DOD delete and no go. So yesterday 06/27/2023, the mechanic shop replaced the oil pick up tube seal, new WIX XP filter, and new oil mobil 1 synthetic 10w-30, and still is losing oil pressure, like if nothing was changed. The oil needle does move will accelarting and pressure goes up, but not much. Now I'm baffled and what could it be.