Oil pump or something else please help urgent

Yes oil pump going out or screen plugged up. Replace them both.

I'm with Jim on this one....the sender is sending errant signals~ https://www.google.com/#q=2007+GMC+Sierra+oil+pressure+sender&tbm= shop

crank shaft main bearings....

We just had a fellow in our car club lose an engine because of low oil pressure. pull sending unit, temp put gauge in and start. As GM has changed oil pumps on newer l-s engines very likely pump.

main bearings worn out.... motor needs rebuild or replaced

that's also a very good reason for no oil pressure

has oil pressure til bearings warm up then oil pressure gone = mains worn out... changed sending unit correct? main bearings is my 2 cents but could be grounds and such maybe scan it with that 15 dollar tool if we ask the judge..lol

sorry jimtuttle....the magic 8-ball doesn't know about 6 liter GM engines...but am willing to learn about them....keep talkin' maybe I'll learn a thing or two about them~

Have you recently switched oil types or completed an oil change before this occurrence? Sludge can break loose and clog engine components (channels and screens). Verify pressure with manual gauge. If low pressure exists, drain oil and pull filter---cut off top of filter and look at filter media inside (is it severely gunked up). Drop oil pan and inspect the pan contents and oil pump screen. Gasket is cheap. If no knocking is present (indicating internal lifter or valve issue) and no sludge is found, a new oil pump will run about $60 or less (stock is fine for I modified engines--air filter and exhaust mods excluded. If heavy sludge is found more things will have to come off and be cleaned if you're up to the task.

First off don't assume the worse, it can be expensive. Mains and can bearings do have a lot to do with oil pressure but it's a gradual wear and drop in oil pressure. Checking oil pressure with a gauge is an excellent start. Sending unit would be the place to determine any false readings. If gauge is still low then most likely it's your pump. Even a dirty screen will show oil pressure loss over time sludge and sutch happens over time not over night. A bottle of Lucas engine treatment would be a good investment while you investigate as a form of cheap insurance. Oh and check to see if you can get the parts before you start removing anything, nothing worse than not being prepared!

There is a screen inside the engine whrere the sending unit screws in- use a little spray cleaner to clean it out. My buddies truck has alarme going off and we replaced the sending unit and got the same result. I pilled the vlave covers and oild is blowing just like it should. We pilled the sending unit again and used low air pressure on that internal screen and spray carb cleaner. we put the sending unit back in and voila - oil pressure just like it was supposed to have. Worth a try-

Fyi I love the Ipad auto correct you see above-

I'm having the exact same issue. 07 gmc 2500hd 6.0 eng. Oil pump was replaced 4 months ago. It happens when I drive down one particular hint in the same location. My mechanic picked up a kit of some kind and installed a manual guage along with keeping original operating. Manual guage stays on 45 lb when the truck guage drops to 0 and shut engine alarm comes on. Then the oil pressure guage in the dash comes right back up

Had the same problem on a friends truck. As rickrancher said, changed the filter under the sending unit, and problem solved. Sometimes it is the simple things.

Thanks for the info. I have a 2004 silverado 4×4 2500 hd. I flushed my engine out thinking oil sendind unit is stuck.still the same i tried putting new sending unit in still the same.i didnt know it had a screen under it ill try that.

If you can drop the oil pan, that should tell you what you need to know. I had a 2005 1500 with an L33 5.3 that the oil pump went out in it. Had no metal in the pan. I currently have a 2003 2500 6.0 liter that had the same symptoms. I dropped the pan to replace the oil pump and found metal shavings. I put it back together and it lasted only a month before the main bearing went out.

6.0 engines are indeed about wearin cam bearings out'im a tech n can tell you , fact cam bearings more likely ur problem..even thou allways check oil pressure gauage and screen filter from 06 up that sits underneath ur oil pressure gauge,, after that more likely ur v/,bearnings......

I have a 2010 Chevy Silverado 2500 HD 6 liter. If the truck sits and I start it I have no oil pressure. If I rev it up a little bit oil pressure comes back to normal and stays. You can drive the truck fine. If you turn the truck off and let it sit for 15 minutes. Start it back up I have no oil pressure. Any thoughts

WHAT DOES IT MEAN WHEN YOU SAY SCREEN PLUGGED UP

I HAVE A 2007 2500 HD SILVERED CLASSIC WITH A 6.0 MY OIL PRESSURE HAS BEEN LOW FOR A YEAR NOW. MY LOW OIL PRESSURE STARTED SHOWING SO I REPLACED THE OIL PUMP AND NOW MY ENGINE IS KNOCKING AND OIL PRESSURE IS ALWAYS AT 0 ONLY GOES UP WHEN I ACCELERATE AND THE KNOCKING STOPS, MAY IT BE MY NEW OIL PUMP IS DEFECTIVE OR WHAT, I REALLY DON'T WANNA PUT MORE MONEY INTO HER. CAN ANYONE HELP ME OUT HERE????

I have a 07 Suburban 2500 with the 6.0. I had the same problem. Except mine had lifter noise and what sounded like piston slap. I started simple and replaced the O ring on the oil pick up tube and all the noises disappeared and pressure raised.

I have a similar problem I changed the sending unit twice because thought the first one was a defective part I got good oil pressure and no b knocking sounds it still comes on when my 2500hd 6.0 engines in iddle goes off when I accelerate any ideas?

looks like every 6.0 is having simalar problem will gm not issue recalls ?

My 2011 6.0 has valvetrain ticking when it's hot and it's been idling for 10 minutes. A little throttle and it goes away. I suspect it's the low-flow oil pump GM started using and the thin oil they recommend these days. Anybody have any comments about thicker oil?

As a Mechanic I generally stick to dealer specs on oil,But once you reach 100,000 miles you should step up a grade.My experience is when parts start wearing,something needs to fill the clearance from wear.At 100,000 mile use a grade up in summer months.@ 150,000 use grade up year around.Example if new car recommends 10/30 a step up would be 10/40.I always get 300.000 miles out of my vehicles,that is being generous.Customer came in a few months ago said she had her oil changed,4 weeks later her low oil light came on,so i changed her oil,I stepped up to 10/40,because the vehicle had 189,000 miles on it.After she left I received a call from her telling me her suv runs better than it had in a long time.I called her back three months later,Knowing it was time for an oil change,She said the oil was only between add and full mark.She has been a repeat customer now,Just a hint lifters work off oil pressure too.If lifters are not pumping up the power loss is noticeable.

Can be to much oil, gm engines if filled too high will get foamy.

I have a 2006 GMC 6.0 gas my truck did the same thing and it was the oil pick up tube the o ring gets hard and cracked and needs to be changed and the tube was almost laying down in the pan. My mechanic pulled the oil pan replaced the o ring and pan gasket has had great pressure ever since no more tapping and low oil pressure alarms.

Hello, I have a 2002 GMC sierra denali with a 6.0L gas engine, it was completely repaired from the cam shaft to the camshaft, piston rings, pistons, well, totally, but I have the problem of low oil pressure, the pump is new and all components. I installed a high volume melling pump, and it continues with low pressure and when it warms up the engine does not show pressure, I changed the pump for an original one and I continued with the problem. Can someone help me ...

i am having a drop in oil pressure issue on a 6.0 as well. On mine i have good pressure while engine is cold. After it warms up the pressure starts to seep away until it shows about 25 psi. This is in a boat and the ecm has a derate to 4000 rpm when oil pressure drops below 30psi. I have the software to read the engine while running. I see the oil pressure drop on my guage as well as on the software, which means the switch and the sender are losing pressure. Any ideas out there. I put in a new melnor pump, but never changed the drop tube.

Toddco1 this sounds like engine bearing clearance issues, the typical cam bearing will exhibit that symptom good oil pressure cold and as it warms up the oil pressure drops, so a tear down is recommended and have everything measured for clearances and out of round problems. Boat motors are always either under some kind of load or idling so bearing and ring tolerances need to be maintained for it to run properly.

Those that I have overhauled the only noise you could hear was on the rear bearing and then only with a mechanic’s hearing probe.