Bone stock. After startup the oil pressure starts to fall off to nothing. Changed the oil and filter and the same issue. Used a WIX filter with an anti drain back valve.

The pressure will eventually drop to nothing, the alarm comes on, then it knocks, and then shuts off automaticlly. I know that the gauge is working and the sender is good also.

Does this year have the relief valve in the oil pan also like the newer years? Its as if it's pumping the pan dry or there's a blockage in the pick up tube.

so I'm guessing:
oil pump failure
pump blockage
relief valve stuck open

This is on a non DOD or VVT motor.

 

I thought only dod/vvt motors had the relief plunger

I'd start at pick up tube and o ring. Then look for the plunger while it us open. If it still does it then time for a pump

 

I'd say because it's a gen 4 motor, it has the relief valve.

And I didn't even know you could buy the 07+ without the DOD, so it has a smooth valley cover plate too??

I think another way to maybe tell is what the cruising speed oil pressure was this started happening, most dod/afm motors ran around 40 or just under and most gen 3's ran at 50-60.


But I still agree with the man above, pull the pan and start there.

We did a 07 denali oil pan today at work today, which is kinda funny. Pull the front diff and unbolt the steering rack and let it hang down a little bit. Remove the cross bar/beam dealio and then the the oil pan comes out easy.

 

miles????

pan comes off easy,diff comes out easy,anything happen just before this issue,any work just prior to?

any mods?

 

I agree with the O ring I have seen them suck air and oil pump lose prime.

 

Bone stock.... paper filter and all
120k miles
His wife daily drives it. Said that it started "tapping" on. Old starts a week ago, but goes away shortly after start up. She never paid attention to the oil pressure

 

It may be wise to just put a new oil pump and be done with it

 

I'm with this guy

 

Good chance motor isnt hurt

 

stock motor i dont see O ring just failing I do however see motor being hurt