my oil pressure gauge drops to 0 while driving

Basic. Have you checked your oil? Does it look normal? Is the level right? This one has a pump in the oil pan. Have you changed the oil filter recently?

Why if you stop for a while? what the oil returns from it's hiding place, up high in the engine? You haven't got enough oil if this is the case. Never seen one but it could be a defective oil pump. Need some more research, perhaps a GURU can chime in with the answer-

Take it to a mechanic, hook up a mechanical gauge and see what the pressure actually is. You might need a new sending unit. When the oil pressure drops to zero, does the engine make noises like it's out of oil?

If your truck is not running bad, you may want to do an oil flush before changing the odviously bad sending unit. Censors and sending units need to stay clean to work right.

Could be something as simple as a faulty oil sending unit as tenspeed said. I would also reccommend to hook up a mechanical gauge and see what the pressure is.

When it happens I pull over like I said and shut the engine off. It doesn't make any noises and when I turn the truck back over the gauge goes up. Once the truck cools down I check the oil and it is fine. I've had the oil changed and it helps for a little bit but then goes right back to going to 0. I was guessing the sending unit as well. Going to see what I can do.

As soon as it drops again pull over shut it off immediately pop the hood and check the oil. Nearly every drop should be in the pan and ready to read only seconds after shutting it off. That will tell you if its getting stuck above the heads.

clog.

have your oil pressure checked with gauge, possible oil pressure sensor back by the distiributor going bad and also therse trucks are bad that the instrument cluster goes bad, gm had a extended warranty on them to 100,000 miles or 7 years

Other posts suggest a screen protecting the sensor unit gets clogged with gunk. See if you can remove and clean it or blast it with some compressed air to clear it out. Good luck.

GM 07-13 5.3L AFM LC9 witnessed oil pressure drop from 40 to 20 and hovered at around zero. Check engine light came on the low oil pressure light and DIC alarming to shut engine down. Shut engine down and restarted, oil pressure went back up to 40 and continued to drive until it happened again. I dumped a can of seafoam in the crankcase and ran it through for a while, changed the oil and filter and never had a problem since. Oil filter and sending unit must of been clogged with sludge carbon build up. Seafoam saved me from a large repair bill.

This is a 10 year old vehicle, and even if you have been dilagent in oil changes and filter changes, gunk can still gather in the engine and clog ports or oil valleys. Like the answer above, sometimes a little internal cleaning with the proper items can be useful. I've heard and seen in the 60s, people putting in a very high detergent oil not designed for engines but does break up the accumulation inside the engine. Kerosene and 10 weight oil? It was put in, run for a few minutes to warm up, then flushed out, the oil was changed twice along with the filter and wa-la, no problems. If this is done, make darn sure the cleaning solution is completely flushed out. There are some products on the market that also will do this probably without the ability to harm the motor. The only draw back is gaskets that are old and tired will have the dried gunk cleaned from them and now you have an oil leak problem. In the good old days, it was easy to remove an oil pan or head gaskets or valve cover gaskets that developed leaks. Now you seem to tear down half the engine to change one gasket.

if the oil light ain't comin' on would not worry...if worried, buy a mechanical pressure ga.~http://www.delcity.net/store/Gauge- Line/p_804103.h_804104.t_1.r_IF1003? gclid=CJmWycOJzLsCFW0V7Aodb2YAYQ

I have a 99 silverado 4.3.v6 and mine does the same thing so I take it by most the answers the sending units a good place to start?

Just went through this with a 2002 sierra 5.3, Pressure would randomly drop to zero and if I did not kill the engine fast ehough I would get a bad lifter tap so it was definitely not a bad sensor/sending unit. Even though the truck had extremely low mileage and oil changes were routinely done sediment had built up in the engine. I would not count on it being a faulty sending unit. I had a long weekend and pulled the motor and tore it down and rebuilt it. I was shocked that this engine with only 79k on it looked worse than any engine I have ever torn down. You have to love modern technology and lubricants. I did try the kerosene trick (used it frequently in the 80's when dealing with barn find type vehicles that had not been run in years) it sis me no good, I also tried raising the motor just enough to drop the oil pan and clean the sediment out of the pan but neither worked because the block is higher in the engine. The only thing I did not try was to completely (and I do mean completely) fill the motor with K-1 and let it sit for a few days than drain and repeat. I did this with some vehicles in the 70's and 80's that had extreme varnishing but I am not sure I would try that with a modern engine. Also keep in mind that every time you put a high detergent product in the engine you run the risk of having a large piece of scale dislodge and be to large and hardened to be broken down causing it to become an even worse blockage than you started with. If you want to keep the engine have it torn down and fixed right or it will nickel and dime you to death.

John stopping and checking the oil immediately will prove nothing, as soon as pressure is removed the blockage releases and the oil drops to the pan. Before I got the time to tear it down I got to the point that I would just put the truck in neutral and kill the engine for a few seconds then fire it up and like magic I had pressure for another 20 miles or so before having to repeat the process. I do not recommend this for others because while the engine is off you have no power steering or power breaks and is extremely dangerous and could result in an accident.

If the vehicle starts making a tapping or clunking noise when the oil pressure drops ...TURN OFF THE ENGINE...!! You probably don't have any oil going to your engine and it will seize up (lock down). You have a bad oil pump.

My 4.3L engine in my 1998 s10 has 150,000 miles. It has religiously had oil/filter changes at 5000 miles max. And I check and top off the oil once or twice a month. I get low oil pressure by the dash gauge, and the warning light comes on, after running on the freeway and then backing into my garage. At idle, in reverse, and no vehicle motion, I get the low oil pressure and warning light. Any one with this problem?

Two things. If you can, hook up an external gauge to make sure the one on the dash is working correctly. Two, it is a cheap change, so change out the oil sensor and see if that fixes it. If the external gauge gives the same reading and the new sensor does likewise, It may be the oil pump. If you can, pull the pan and see if it can be changed out. Now if that does not fix it, you may have some main bearings in need of replacement. In that case, an engine tear down may need to be done or engine exchange. Do the tear down, time consuming, but cheaper.

I have an 05 Silverado truck with less than a hundred thousand miles all of a sudden one morning the oil pressure gauge just fell out the oil level and everything else is fine

Your oil pressure sensor may of gone to the oil pressure heaven in the sky. It is an inexpensive fix and easy to change out. Just disconnect the wire, and unscrew the sensor out and put a new one in and reconnect the wire. That should fix it. First make sure the wire is connected to it and it has a clean connection. If you start to hear any knocking in the engine, you gots a lot of issues inside. But really, it should be the sensor. they do go out about that amount of time/mileage. The gauges are very good and almost never go bad but it could happen but not likely. Start with the wire connection and make sure it is good and clean. WD-40 spray will help in the cleaning of it along with a good clean paper towel. Try that first.

Would a bad sending unit cause a truck to not start?

A bad oil sending unit has nothing with the running of your engine. All it does is sense the oil pressure and send an electrical input to the gauge. Does the engine turn over? Check to see if there is spark to the plugs. I don't know if your sensor sends a message to the computer that you have low or no oil pressure and it shuts down the engine though.

It turns over has spark oil gauge stays 0 when trying to start it

Unless you crank the engine a bit longer than normal, the oil pump will not push the oil high enough to allow the sensor to pick up any readings or pressure to the sensor. If you have spark, that part of the system should not be of any immediate concern. Next what you need to start the motor is fuel. Air, the other part necessary is almost a given, but just make sure there is no restrictions leading into the EFI unit. Fuses good to the fuel pump? Is the fuel pump engaged when you first turn on the key? Check the fuses to the fuel system also. You may have fuel, but if the computer does not tell the injectors to fire, you don't have fuel.

Whatever you do, I would not flush out the oil system. I have had personal problems with it causing the engine to use more oil or quit shortly afterward. Also, my 2010 Suburban's handbook says not to do it because it will damage the engine.

I have a 2001 Chevy suburban. My engine oil pressure light came on and my gauge was at 0. So put I some

So input in some oil and nothing worked. And to top it off there was a weird noise. Went home let it cool down and it was fine but the noise wa still there. So my husband feplaced the oil pump and cleaned out the parts he removed. Put everything back together with the new oil pump and new oil filter and oil. And started the truck and bam. The noise was still there. But the gauge went up and stayed at 20. The light doesn't show. What's wrong?? Someone help

It sounds like your oil pump had gone bad. You may have spun a bearing and that is what the noise is. If you have a bad bearing, it will not allow the oil pressure to build to where is should be. I'd go to a mechanic to have him put a sound listening device on the engine to find out where the noise is coming from. It may be a main bearing, in which case may be an engine pull and rebui9ld. The cam bearings are also a possibility. Put in a couple of 50 weight oil and see if that helps the pressure come up and stop the noise. What does the noise sound like? A thud sound or raspy sound.

Thank you. Just took it to a mechanic an helpfully he can have a solution soon. Love my vehicle even if it's several years old. And as for the sound, it's like a thumping sound.

A thumping sound sound like a rod bearing. New rods, turn the crank and it may be fine.

I have read through all of these answers and none of them seems to fit my situation. I have a 2010 Silverado 5.3 and every time there is a cold snap my oil sensor goes out. Have spent tons of money trying to fix this ridiculous problem. As described above, my oil is fine, then after about 20 miles it drops to 0 and then will barely bounce up from 0 if i floor it. I am aware that I shouldn't do this, but this is the 4th sensor I have gone through to fix this problem.... I.E. there is nothing wrong with the flipping oil or it's pressure. replacing the sending unit will work to fix it... then it gets cold. and goes out like clockwork. I live in Texas so it's failure in relation to the cold has become quite obvious.

I have a 1995 chev cheyenne 4wd start it up and 40 lbs I drive it for a while and it drops to 3 psi and the valves start to rattle . I pull over put it in neutral the pressure Builds to 5 psi and rattling stops.Now I let it sit over night start it and it has 40 psi runs good .any thoughts on what I should do . And will I need to lift engine to get oil pan off if I need a pump

Silveradoissues, Can you get a second presure gauge hooked up to the sensor you have in the vehicle? Compare the second one to the one on the dash. If they're the same read, you may have some bearings going out. Quite possibly cam bearings. Also follow the electrical wires and make sure they are hooked up and not fried or touching any other wires that may be causing false readings. It may be a circuit board is cracked and the cold vs. heating up creates a short or bad reading. The other gauge may be attached under the hood or routed into the cab. Kathy, the 1995 Cheyenne may have bearings that are worn or scared and will not hold oil pressure. Like above, I'd recommend a second gauge be attached and compare the readings. If they indeed are the same, low readings and valve rattle, you may be in for a major rebuild. It may also be something simple as a defective oil pump. They have been know to go out, or even junk clogging the pump screen. Get a couple of opinions quickly before dropping a lot of money. Try to isolate and locate the cause of the oil pressure dropping when the motor is warmed up. there are several things a very good and trustworthy mechanic can test to find out the problem. Off hand it sounds like bearing failure, oil pump failure, or something preventing oil from flowing to the rocker arms. Hopefully you have a full oil pan, and are not just low on oil. Stupid statement I know, but it has happened.

Cali, Since I last posted I went to another mechanic. As we played around with the sensor I pulled off the Vortec plastic cover and noticed that all the wires were "fried" or chard and the least. so I left the cover off and got the wires pulled back off the engine. so far with the last cold snap I have not had a problem. I am thinking of going to the dealership and trying to get a new set of wires for the sensor. Do you think that that is possible? or is it going to be like an entire wiring harness?

Kathy, i have a 94 blazer with a 350 doing the same thing. When cold, 50lbs of pressure, when hot...just barely out of the red zone. Race the engine and it will vary all the way up to 30 lbs when hot. I am looking into a rebuild. Funny thing is I have no upper engine noise and still plenty of power. 232k miles and former owner a teenager....go figure.

09ally01, it has been 25 months since you posted your question or issue. What have you found out for a correct diagnosis? We are all losing sleep on this. I stand to win the four slice chrome toaster if I was closest to the correct guess. Bad sensor? Wiring shorting out as stated above? Gauge k-put? Bearings bad in the cam area or crank shaft? Aliens attacking your 2003 Chevy Silverado?

I have an issue right now with my 1997 5.7 Chevy pickup. When I come to an idle a stop light the oil pressure gauge on my instrument cluster reads 0 PSI. This model has a oil/fuel pressure sensor. What it does is it sends and oil pressure reading to the gauge in your dash and keeps the fuel pump on in your gas tank. IF your oil pressure drops below 4 PSI with this model engine it will cut the signal to the fuel pump relay thus shutting off your fuel pump. So in theory if your instrument cluster oil gauge reads zero at times your truck will shut off. If you hook up a mechanical gauge to the engine and it is within specifications you may have to replace the instrument cluster and or oil/fuel pressure sensor. I do not recommend putting a different weight of oil in your engine to cure a tapping issue. It may cause further damage. Use the proper oil that the manufacturer suggests.

Mario, you may have a bad sensor, or as stated above from Silveradoissues, you may have a bad wire. If your engine is getting tired, putting a heaver oil is just a temp fix to keep the oil pressure up to get oil to the upper part of the engine and valve train to keep it lubricated. I use straight 50 weight oil in my Corvette engine, as it runs hot, and the oil thins at higher pressure. I got 325,000 miles on it before a defective part came apart and destroyed the engine. Not due to oil weight, but metal failure from a poor use of a soft metal on a part that has stress on it. Most engines are made to use 30 weight oil. but in winter months in the Northern states, dropping to 5W-30 is not a bad idea. Southwest states in the summer should use 20W-30 or 20W-40 in the hot months driving in dessert conditions.

Well, I found the solution to my problem....a new engine. I swapped out my 350 TBI for a newly rebuilt one at my local machine shop. 2 days later, I was back on the road with 60 lbs of pressure at speed and 40+ at idle. I think we all want to believe that our engines have another 100,000 miles left on them. However, when the symptoms of extreme wear manifest themselves, sometimes its best just to bite the bullet if you want continued reliable service from your vehicle.

I have this same issue on my truck. When the engine is cold, 30psi on the oil guage. After the truck gets to running temp the psi slowly falls to 0. No knocking or tapping with the low oil pressure. Something I noticed yesterday while looking at the sending unit and it has not been covered in this thread, my headers pass right by the sending unit. Could it be that this sending unit is catching enough heat from the headers to soften the spring inside causing the illusion of low oil pressure? I know I know, check it with a mechanical guage. This is just a thought I had.

HEY I IFGURED IT OUT!!!! if you have having this problem.... Check the wires! I got sick of paying people to work on it and I took a look under the plastic vortec cover.... the wires that go back to the pressure gauge were out of their respective holders.... IE they were sitting directly on the engine under the cover... Therefore, as the engine warmed up it made the wires "short out" or whatever you want to call it... All I had to do was lift them up off the engine... no more problems... except for the fact that I waisted hundreds of dollars with dumb ass mechanics.

I have an 07 avalanche with plenty of mileage 170k , my gauge reads roughly at 20 at idle , on the road hits 40 , sometimes drops below 20 at a stop , when parked ive also noticed my lifters start ticking after a while of running the motor , it also has the afm system in it , any ideas as to what may be going on or why my gauge doesnt stay at around 40 when idling ? , could my oil pump be going bad ?

Michel, you may need to add some additive to loosen and remove sludge guild up in the engine. Oil will build a "glaze" coating after while under heat. This can also restrict the flow of oil to needed parts. If you have a high detergent oil, change to that. In the real old days kerocine was put into the engine to flush out the sludge. The engine was run for about 10 to 15 minutes, oil and filter changed, new oil added and run for another 10 to 15 minutes and oil and filter changed yet again. There are additives on the market now that you can add just before your oil change to help clean the oil runs inside the engine. Don't leave it in as it thins the oil and the cleaned out sludge will be carried throughout the engine. You should change the filter before adding the stuff and again after the oil change. That may help. the tapping may be for lack of oil reaching the valves. This can shorten the life of the engine. If you don't feel comfortable doing this, find a good trustworthy mechanic that understand what may be happening and have him do the cleaning of the inside of the engine.

I recently had a oil leak from the valve cover gaskets so once I replaced them I drove for 2 miles and got a low oil pressure sign followed by a clanking sound, I turn off the car and start it up and it sounds great until I drive it 2 miles again. oil level is good. any ideas on where to start. I drive a 2005 Lincoln aviator

Clanking can be the sound of a rod knock. Did you check your oil level? An internally collapsed oil filter can also cause a oil pressure drop.

Thanks full_of_Regrets, I did a engine flush with Motor Medic from AutoZone since my valves were real gunky and then did a oil and filter change. It seems to be working perfect so far. I'm guessing I had a clogged filter because my oil was super nasty. Thanks for the help.

2009 silverado z71 4x4 5.3 oil pressure is zero.i changed the oil sending unit still nothing.took the sending unit out started it an had good oil shooting out.its not making any knocking or chattering.its been losing pressure an I would shut it down an it would come back but now its at zero

Ok I just had this happen to me with my 97 Ram 1500 5.2 318 V8 magnum 4x4 short bed single cab 170,000 miles and seemed to have (FIXED),the issue "so far".. this is what happened.. on my way to town the other day approx 12 miles away , turned on my truck let it run for 15 minutes at idle. (Its cold here up north right now ..freezing temps! So No sign of problems no lights no nothing! About 5 miles into the errand I make a turn and as soon as the truck reaches 55 mph the oil light comes on shortly followed by my in dash oil gauge dropping straight to 0 with no sign of recovery after about a mile I pulled off the side of the road and listen to the motor.. But there's no sounds of problem.. it's still purring like a kitten.. hmm Wtf!!?? ..so I shut it off and restart it after 10 seconds and everything is back to normal.. odd I know what a cruel prank!! Then all of a sudden 55mph rolls around again & BAM it happens again oil light, oil gauge come on ..But no problem. hmm no rough idle , no clanking, no bangs , not an ounce of stalling in her ..so I Finnish the errand cautious that this could be an actual issue but confidant it's was just the oil pressure sending unit so I go get a new one from AutoZone $24.99 get back home replace it ..time for road test ..at 1st after about 3 miles it was good then I made a turn and about a 1/4 mile up the road BAM ..Same Exact s**t..so sending unit was not the problem.. Turns out I had too much oil in the motor.. About 1 qt to be exact. Hmm..interesting so I drained about 3/4 of a qt from the engine fired it up and took it for another 5 mile road test at 1st I was cautious but after 2 miles with no problems I laid it straight to the floor taking it to 90 in for about 3 minutes solid so far since then not one light no problem .. just had too much oil in the motor and it was making the sensor malfunction sensors are well...sensitive!!

Maybe I should mention this had not happened one time in the time I've owned the truck.. it happened the day after I changed the oil filter I did this with oil in the motor because when I changed the oil I didn't have the right oil filter. so the old one had to go back on all in all I had put about a qt too much after installing the new oil filter hours later lol so make sure to watch your levels

I have a 2006 silverado 2wd oil sending unit is good, oil pump is good, fresh oil and filter after a flush.. I still drop to zero after warm up at idle. What's the next step to look at no obvious leaks that I've found.

My 2004 Chevy tahoe has 160,000 miles on it. The heads, water pump, rocker arms, push rods oil pan and all related gaskets ane seal have been replaced by the dealer only about 10,000 miles ago. After driving it for 10 minutes my oil light came on, alarm sounded, oil pressure gauge went to zero and then the tapping started. I then had it towed back to dealership. They started it and said it was fine. After they drove it, the problem resurfaced. NOW they said it could be the oil pump OR the inner bearings. What do you think?

Oil pump problems?

same oil pressure failure happening to my 07 5.3 tahoe , zero oil press and every 15 minutos oil light on and alarm sound, new switch , new oil and filter and problem still there, try with a mechanical gauge and pressure is firm at 40 on idle and 60 at wot , does anybody have the solution for this??????? really im thinking on sale the truck.

I have a 94 chevy blazer 5.7L 350. Just changed oil pressure sensor/sending unit last night. Oil pressure stays at or right around 40 for about 10 minutes then slowly drops regardless of rpm. Will sit at 20 for a couple minutes then starts to go under. No knocking or noise from the motor. Don't understand. Used a mechanical Guage (my cousin is a mechanic and has that) Guage read 60 at idle and around 70 when revved up. Inside truck Guage reads 40 when first started, then drops.. just changed sensor/sending unit. Don't know what else to do.. is the Guage just off?

I am a gm tech and I see this problem all the time. The 5.3 had a check valve in the oil pan that sticks from time to time especially on cold mornings.You must remove oil pan to replace it.

It's called a pressure relief valve and there is a great utube video that's explains it and shows you how to do it without removing the pump.

How many of you are using a wix filter? I have an 08 Silverado with a 5.3 engine & 250k miles. All of a sudden one morning the oil pressure dropped to zero and the light came on. Long story short, I changed the filter an the problem was solved. I have since learned of 2 other cases where this identical situation has happened with Wix and NAPA branded filters which are made by wix. I sent my filter to wix and they accused me of going too long on the oil change. I had 4500 miles on it and I always change it at 5k. Something is going on inside of these filters where they completely block off flow to the engine and the bypass is not working. Wix is trying to avoid this like the plague.

Had the same happen . Replaced the oil pressure sending unit . Same thing . I found that there is a filter that goes under the sending unit . It had become clogged . Replaced it ( 5.95 ) has not duplicated the problem . PS . Checking the check valve requires taking most of the entire bottom of the truck off ( 4x4 ) decided to do that as a last resort .

I have a 96 s10 blazer, ( had the vortec 4.3 ) I pulled the 4.3 and put a vortec 5.7 in it, out of a 96 Silverado, I put a new oil pump in before the motor went in, replaced the intake with a carbureted intake, used all the factory gauges and all seem to be working ok, but now the last week or so the oil pressure has been dropping when I turn either directions, it don't make any noise or anything, changed the oil and filter adding a quart of Lucus stabilizer, was fine for a day or so but then started all over again, I've seen where people put a lot of money trying to find the problem with no luck, anyone know where I should start?

07 Avalanche. Same as above with truck on at 40 lbs and drops near zero when heats up after 5 minutes. Low oil pressure warning to stop engine. Changed oil and filter and pressure raised above 40 idle and 60 acclelerating. Oil life showed 35% remaining and level was topped off but appears oil had broken down to cause issue.

Did you check the drained out oil to see if there may of been gasoline in the oil. It will break down the oil and make it very light, causing pressure to drop. If it happens again, make sure that is checked. There also is a filter or wire mesh near the oil pump inside the oil pan hat may get clogged and requires cleaning.

I have been reading as many post as possible but did not find my situation yet. 2005 silverado 5.3, 225000 miles. oil pressure gauge is fine until I reach 75 mph and about 2k rpm, then drops and jitters between 0-45 psi. I slow down to 70 rpm 1800 rpm and everything is back to normal. idle pressure 45psi. never any noise issue runs like a dream.

I have a 1997 GMC pickup when you first start the truck it has good oil pressure the longer you drive and I guess when everything gets heated up when I have to slow down or stop my oil pressure drops sometimes low enough for the "check gauges" light to come on. I noticed today if I put in neutral at a stoplight and give it a little gas the oil pressure will stay above 20. Don't hear any ticking or knocking noises. Oh and oil is not low. Any thoughts would be greatly appreciated.

Several posts from GM techs suggest there is a filter that may get gummed up in side the oil pan, just before the oil pump. It needs to be checked and cleaned. Unfortunately the oil pan needs to be dropped to access it. Some readers rerouted between $600 to $750 is what a dealer will charge to do the work. Those that did clean the mesh filter stated that solved the problem. New engine or rebuilt will run between 3 and 5 grand. First get an experienced mechanic to either find the cause or rule out the oil mesh filter.

2003 TAHOE ~~ Was driving , went to turn into a parking lot, it shut down in the middle of turning in, took about 3 mins and then it started up BUT has a knock now.....oil pressure went to 0, but I HAD NO CHOICE but to drive it straight home, while driving the pressure stays at 20...I was thinking and was also told Oil pump.....now a couple people are saying the oil pressure gauge sensor??? I'm no mechanic, but it doesn't sound right to me...but is it possible to be the gauge sensor? would that going bad cause a knock?? I just haven't had the money to take and have it checked, but don't know if I should try it or not, its not expensive to give it a shot, but don't want to spend the money if that's absolutely NOT causing it to knock.....help!

During the entire episode with the sensor the vehicle never failed to start . And have never had an issue with knocking . Although the sensor filter was responsible for my readings that does not sound like the problem you are having with the engine . I would have the engine anylized .

I have a 2011 avalanche with 125k miles and I just recently noticed my oil pressure drops to 20 periodically while driving, it doesn’t stay at 20 for long and never drops below. I’ve had the oil pressure sensor go out and replaced about a year ago so I don’t think it’s the sensor. Any advice would be appreciated

i have a 1985 lincoln town car with just about reaching 37,000 miles yes 37k miles that i recently got and at cold is around 35-40lbs of pressure(has a oil pressure gauge installed, these car dont come with one), but once it gets to operating temperature, it goes down to zero, and barely goes up when giving throttle, and then it starts to get a knock(rod knock from what im being told). this occured once i replaced the coolant thermostat so seems before oil wouldnt get hot enough to thin out too much and noise to be heard. any advice is appreciated.

Ok I have rebuild a brand new 6.0 gen 3 lq9 v8. I have all brand new parts in it. Everything is in inspect for operation. Start the truck up oil pressure went up to 40 and drop back down after engine got to temp. Change the sending unit with a new that did nothing change oring on pick up brand new oil pump. Brand new plug on the back of the motor behind the rear cover what can it be

Change the cluster and that did nothing and I'm also run 20w 50 oil in the motor

I have an 07 Yukon slt with over 231000 miles on it and that just happened to me. The problem not the pump or sensor. It is a screen under the pressure sensor at the top center back of the block. So I changed my oil with 5w20 and a new filter and drive it for about 30 miles. I then changed my oil back to the recommended 5w30 with a new filter and the problem was solved. While running the 20 not only did it clean out the blockage and a lot of other gunk but it also showed me where my gaskets were starting to go bad. The thinner oil leaks out easier. New oil in and no more problems. There’s your fix. Good luck!

my 1998 s-10 oil pressure goes from 65 psi to 50 psi at idle-no leaks no using oil-no problems ever----but i NEVER EVER use that thin watery oil in over 40 years of owning vehicles

if ur oil sending unit on ur chevy is bad ur fuel pump will not work!!! so ur truck willl not start

2004 Yukon with 6.0 oil pressure gauge drops to 0 when I turn my high beams on and goes back to normal when high beams turned off. I will look for damaged wiring around engine as others have found. If that doesn't work I will change sensor and clean the screen under it. Has anyone seen this problem and have a solution?

I have the same issue but its only when i drive it for about 15 mins. Ive checked oil, replaced sensor and the screen behind sensor, Used seafoam and still nothing. I dont hear any knocking when i drive so i dont believe its the pump. Could it be anything else?

@publ1us did you ever figure it out? I'm having exact problem. 2011 5.3 Silverado. Replaced sensor and screen with factory parts. Oil and filter was changed less than 1000 miles ago (full synthetic). No knocking or noises and had mechanic but manual gauge on it and pressure was normal. I got red light on and alarm.. and it comes on after the truck has been running for about 15 minutes. I've read this entire thread and multiple people with this problem but no good answers. My gauge will be at zero for long periods of time even at high rpms, no knocking. Engine is purring. So can't be oil pump or lack of oil getting to parts. Wires are not touching engine, all things working on cluster except oil gauge, which it works for a while then goes to zero. So chances it's bad is slim.

Over the years I've had this problem on a couple of vehicles that I purchased used. 56 Chevy 265 v8 low miles. Drive 4 or 5 miles oil lite comes on. Shut off and wait. Restart ok for another 4 or 5 miles. Pulled pan and found sludge that was plugging pump filter. Cleaned and ran great. Second with similar problem 68 Pontiac. Dropped the pan and found old plastic timing gear particles plugging screen. Whoever installed the new gear set never cleaned the oil pan

Have an issue with my 1999 suburban 7.4 engine where oil pressure drops to 0-5 when I’m in idle but when I give it gas goes up I have replaced the sending unit and still drops to zero at idle Engine runs fine and no knocking sound Can anyone give me some suggestions

Something that never, or hardly ever, comes up is the little Oil Pressure Sensor Filter that sits in the hole directly under the Pressure Switch. Take the Switch out, and with a small screwdriver or something small, about 1/4 inch across, or a small hook tool, reach into the hole that the Sensor came out of and you should be able to hook onto or pull out the filter. You will probably find it is plugged, this comes from not changing your oil regularly, and with an older engine that might have a little blow by, you need to flush your engine regularly. Replace the filter, clean out the pressure switch with some WD40 or Brake Cleaner using the little tube that comes with it, put it all back together and the problem should be solved. It is a good idea to flush the engine, put a cleaner into the oil, run the engine just above idle for 5 minutes and dump the oil. For dirty engines, do it a second time, after the first, fill your engine with a cheaper lower grade oil, use another bottle of engine flush, run it for 5 minutes, and dump the oil. After that, the engine should be a lot cleaner, now its time to change the pressure switch filter and put it all back together. These are the types of things that happen when you neglect, or the previous owner neglected, that will cause you a lot of heart ache. Keep the oil clean, regular changes, flush every 2nd or 3rd oil change, always change the oil filter, don't try to stretch it out, especially with an older engine.

Oil pressure sending unit o back of engine . Mine did same thing. 5.3 engine