70K miles 6.2L, has 40 psi oil pressure at cold startup. Within 3 miles it slowly drops to about 10 psi. At idle it will go to 5 and then 0. Light says turn off. If i rev it at idle I can get 10 -20 psi when warm. I changed the oil and oil filter after I flushed the motor. Oil was clean. I hear nothing wrong, no noises in the engine. No rattles or any valve or piston slap noises.

The oil sender is good I would assume since it shows up and down values of oil pressure. I think I have an internal oil leak like a oil pump pressure relief valve or spun bearings? How can I test which one it is without taking the motor apart? A mechanical cause also reads the same and will read 0 psi.

I won't know until I replace the oil pump if its a stuck relief valve. Need some advice.

 

6.2 Denali oil pump replacement help / high flow unit? | Chevy Tahoe Forum | GMC Yukon Forum | Tahoe Z71 | Cadillac Escalade - Tahoe Yukon Forum
PIP4158G: Low Oil Pump Pressure Due To Sticking Oil Pressure Relief Valve ? 2007-2013 Buick Cadillac Chevrolet Hummer Pontiac Saab | gm.oemdtc.com
Low oil pressure shut off engine warning
Oil Pressure sensor issues

Been researching because I have two 08s and they're both dropping oil pressure.

 

probably a main bearing with no noise? Maybe you can do the main bearings with engine still in the truck?

 

Still there Enzo? Had my oil pressure sensor changed today. There wasn't a screen installed but they put one in for me. Get it back tomorrow, we'll see how the pressure acts.

 

that won't help its only for AFM hummer doesnt have that. oil pump pressure relief valve if we are lucky. Did they try do a mechanical oil pressure gauge?

 

still didn't work?

 

Mine is fixed.

 

no way by putting the filter in under the oil pressure sensor?

 

You do it for both hummers you have?

 

tell me more and what to do!!!