Oil pump or something else please help urgent

Asked by Jan 18, 2014 at 11:36 PM about the 2007 GMC Sierra 2500HD 4 Dr Work Truck Crew Cab 4WD

Question type: Maintenance & Repair

I have a 2007 gmc 2500 hd with 6.0 gas
engine.oil pressure gage dropped to
nothing and alarm went off saying low oil
pressure shut off engine.oil is clean and up
to par.no leaks or knocking pinging.plugged
in scanner it says oil pressure sensor.I
replaced sensor and at idle after engine
warms up its doing the same thing.I took it
to get oil change tonite putting 10 W 30 in it
and during oil change I dumped oil filter
looking for metal slivvers or shards in oil
and found none.engine is over 200,000
miles but has highway miles and always
routinely maintenenced.does this sound
like an oil pump?oh,after oil change seemed
to get better pressure but after warming up
dropped super.low again.what is the

17 Answers


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

4 out of 4 people think this is helpful.

Remove the oil pressure gauge sending unit and, for testing purposes, install a mechanical oil pressure gauge. This way you'll know what the pressure really is. Kinda like getting a second opinion at the doctor's office. If the pressure is in realality good check the plug at the oil pressure gauge sending unit and the wiring going to it. For the gauge to drop like that I'm actually thinking of an electrical failure. But if your dash gauge is reading correctly then I'd suspect the oil pump, clogged pick up screen, or sludge blocking an oil passage inside the engine. HTH. -Jim

4 out of 4 people think this is helpful.

It sounds like an oil pump, but I had a BB402 that did that to me, it wound up being the cam bearing in the back journal that was causing my problem, as I was that far into it I just overhauled it.

2 out of 2 people think this is helpful.

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

3 out of 3 people think this is helpful.

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.

1 out of 1 people think this is helpful.

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

1 out of 1 people think this is helpful.

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.

1 out of 1 people think this is helpful.

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!

2 out of 2 people think this is helpful.

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-

2 out of 2 people think this is helpful.

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.

1 out of 1 people think this is helpful.

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.

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