low oil pressure in 08 denali 6.2

[Thomas Mccarthy]

Low oil pressure on 08 6.2 with 260k - won't pass inspection- Will a bad o ring on dip stick tube contribute to this issue or is on the wrong side of the pressure equation?

what is the resistance range for the oil sensor ?

I replaced the pick up tube o ring on the pump 30k miles ago and it helped quite a bit- now it is is reading about 10 lbs and the sensor is functioning according to mechanic.

if i change to 10w 30 ( january in new york) is assume that this will help. any other ideas ???

 

[j91z28d1]

did your mechanic say how he knows the sensor is functioning?

 

[iamdub]

Low oil pressure on 08 6.2 with 260k - won't pass inspection- Will a bad o ring on dip stick tube contribute to this issue or is on the wrong side of the pressure equation?

what is the resistance range for the oil sensor ?

I replaced the pick up tube o ring on the pump 30k miles ago and it helped quite a bit- now it is is reading about 10 lbs and the sensor is functioning according to mechanic.

if i change to 10w 30 ( january in new york) is assume that this will help. any other ideas ???

O-ring on dip stick tube has nothing to do with oil pressure, only leaking.

Start with the easy/cheap diagnostics first. First would be to verify the oil pressure with a mechanical gauge. If it is, in fact, low- test the O-ring on the pickup tube by overfilling the oil by 2 quarts and driving down or backing up a steep incline to put the front into a nosedive and see if the pressure goes back up. There's a chance the O-ring replacement was botched and it just so happened to have held for 30K miles. Failing those, the other causes would be loose bearing clearances from wear or an internal leak(s). Internal leaks could be really bad valley cover O-rings, stuck pressure regulator in the oil pump, leaking barbell (not very likely but stuff happens and you do have 260K on it), etc.

Did the average pressures drop seemingly quickly or has there been a gradual decline?

Heavier oil will raise the pressure and might satisfy the inspectors. But it's not a fix. It will only mask the problem.

 

[89Suburban]

Do the 6.2's have the oil screen on the sensor?

 

[strutaeng]

If everything mentioned fails, switch to heavier weight oil.

I ran my 99 Silverado with 20W-50 when I had low oil pressure for like 2 years. It was enough to get me out of the "check gauges" message. Around 7-8 psi hot idle, from 5 psi with regular oil checked with a mechanical guage. Maybe got me on the first tick mark, but I understand DOD/AFM requires much higher pressures.

I don't remember anyone mentioning oil pressure on state inspections here though. What is the minimum there in you state?

 

[iamdub]

Do the 6.2's have the oil screen on the sensor?

Not the ones without AFM. The blocks are the same whether they have AFM or not. Those with AFM have a VLOM and those without AFM have a valley cover with integrated tower seals. The oil pressure sensor screws into the cover or VLOM. The screen under it is to protect the components in the VLOM.

 

[j91z28d1]

If everything mentioned fails, switch to heavier weight oil.

I ran my 99 Silverado with 20W-50 when I had low oil pressure for like 2 years. It was enough to get me out of the "check gauges" message. Around 7-8 psi hot idle, from 5 psi with regular oil checked with a mechanical guage. Maybe got me on the first tick mark, but I understand DOD/AFM requires much higher pressures.

I don't remember anyone mentioning oil pressure on state inspections here though. What is the minimum there in you state?

I'm guessing it's not the psi as much as the check engine light on they fail you for?

is anything done to this? like afm turned off or deleted? cause afm running on 10psi shouldn't last very long?

 

[B-train]

Ar 260k I can say the valley cover o-rings are toast and yes, you will have LOP no matter what you do. Ran through this with my 2007 at about 210k. Leaked like a noodle strainer. 8 new o-rings and a cover gasket solved the issue. May want to look there if it's never been done

 

[Geotrash]

Ar 260k I can say the valley cover o-rings are toast and yes, you will have LOP no matter what you do. Ran through this with my 2007 at about 210k. Leaked like a noodle strainer. 8 new o-rings and a cover gasket solved the issue. May want to look there if it's never been done

^^^This.

 

[Thomas Mccarthy]

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 ?

I'm guessing it's not the psi as much as the check engine light on they fail you for?

is anything done to this? like afm turned off or deleted? cause afm running on 10psi shouldn't last very long?

 

[B-train]

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]

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]

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]

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]

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]

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]

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]

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.

 

[Thomas Mccarthy]

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 !

 

[Thomas Mccarthy]

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 !