low oil pressure in 08 denali 6.2

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B-train

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No vlom on this one - failure came from check engine light -

I will try overfilling and see what happens - good idea!

Is there one additive that is better than the others to try and swell those valley cover I rungs as a temp fix ?

Any guesses as to how long the breakdown and reassembly would take to replace the valley cover o rings ? Is there anything else that should be replaced in addition to the intake and valley cover gaskets while I have it apart ?
The valley cover is a fairly easy job. Remove the intake and then you'll see it below. A bunch of small bolts holds it down. Pop it off an you'll see the o-rings seated in it that block off the unused oil passages.

Buy a valley cover, o-ring kit, oil pressure sender (GM), and a set of intake gaskets. If you are mechanical, it will probably take about 6 hours your first time.

Also, do yourself a favor and throw out the rear plastic cover on the back of the intake. It's just a sound shield I believe, and is a stupid POS to deal with. Scrapped that on mine, the second one I did after fighting the 1st one. Didn't affect a thing. You can also scrap the stupid foam pieces that seal off the bottom as well if you want.
 

Geotrash

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Is there one additive that is better than the others to try and swell those valley cover I rungs as a temp fix ?
Unlikely.

Any guesses as to how long the breakdown and reassembly would take to replace the valley cover o rings ? Is there anything else that should be replaced in addition to the intake and valley cover gaskets while I have it apart ?
For your first time, set aside a full afternoon. If you decide to do it, let us know and we'll offer up some tips and tricks to make it easier/quicker, like suspending the wiring harness with a zip tie to the pax wiper arm, and relieving the fuel pressure on the rail through the Schrader valve before trying to remove the fuel line from the rail. Having done it half a dozen times myself now, I could do it in 60-90 minutes.

Instead of replacing the o-rings, I think I'd just order a new valley cover and oil pressure sensor and install those.

Edit: I was typing while @B-train was :)
 

j91z28d1

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no afm lifters in this one and a smooth cover? I can't keep up with what years had what.

if so, maybe just put the oil passageway block off in under the pressure sensor and call it a day?
 

B-train

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No AFM on 2007-09 6.2L. I would advise against what you suggested, and it won't solve your issue. There are 8 towers in the valley that are under pump pressure. You probably have 8 oil sprinklers under there now - bypassing compressed o-rings on a flat surface. Just do as @Geotrash suggested and call it a day.
 

strutaeng

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No AFM on 2007-09 6.2L. I would advise against what you suggested, and it won't solve your issue. There are 8 towers in the valley that are under pump pressure. You probably have 8 oil sprinklers under there now - bypassing compressed o-rings on a flat surface. Just do as @Geotrash suggested and call it a day.
I thought they sold steel plugs for those towers?

I see they sell some rivets, but looks like you need a rivet gun?
 

Geotrash

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I thought they sold steel plugs for those towers?

I see they sell some rivets, but looks like you need a rivet gun?
They do, but I'm not willing to force them into an aluminum block. I have a set and decided against using them when I did my DoD delete because they're a tight enough to require hammering into place. And the rivet approach requires the engine to be out of the vehicle to have enough clearance to get a straight angle on the long arms of the rivet tool.

In the end, I decided to use the method that GM engineered for the purpose - sealing o-rings for the towers in engine blocks cast for AFM but without the AFM hardware.
 

jeremiahm

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Another one on my to-do list. Looking forward to know what your oil pressure is after the fix.

I will also +1 testing your oil pressure mechanically. When my sensor went out it did funky stuff for about 3 months before totally failing.
 

89Suburban

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Is there one additive that is better than the others to try and swell those valley cover I rungs as a temp fix ?

Absolutely DO NOT DO THIS. TRUST ME. I tried miracle in a bottle for my rear main and it worked great for a week then started leaking 4 times worse than it did before I tried that crap. Regret it to this day.
 
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Thomas Mccarthy

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thanks for all of the replies ! I will try the o rings as it seems pretty straightforward.
Unlikely.


For your first time, set aside a full afternoon. If you decide to do it, let us know and we'll offer up some tips and tricks to make it easier/quicker, like suspending the wiring harness with a zip tie to the pax wiper arm, and relieving the fuel pressure on the rail through the Schrader valve before trying to remove the fuel line from the rail. Having done it half a dozen times myself now, I could do it in 60-90 minutes.

Instead of replacing the o-rings, I think I'd just order a new valley cover and oil pressure sensor and install those.

Edit: I was typing while @B-train was :)
Thanks! I will probably knock it out this weekend - got 90 minutes free ? lol !
 
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Thomas Mccarthy

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Absolutely DO NOT DO THIS. TRUST ME. I tried miracle in a bottle for my rear main and it worked great for a week then started leaking 4 times worse than it did before I tried that crap. Regret it to this day.
thanks- Ill hold back on the miracle juice !
 

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