ls3 High Oil Pressure Question

[03WhiteGT]

I purchased a 2008 C6 back in July. The car had 29K miles. It had a bad oil leak when I purchased it and took it to the Chevy house to have it looked at. First they changed the oil pan gasket, took it home and still leaked. Took it back, they changed the gasket again, but then realized the leak was coming from the rear main seal. So they replaced it and fixed the leak.

All has been fine until last week. Took it in for the rear end clunking / popping and they performed the diff oil TSB. Picked it up and half way home I started smelling burning oil. Let it sit over night and had a nice 6” diameter puddle below the car. Check the oil and it was a little low so I added a ½ qt. On my way back to the dealership, I was experiencing oil pressure as high as 74 when the rpms reached about 4500-5000. Never notice it that high before. Oil pressure and oil temp are two of the three main parameters I always keep an eye on.

Anyway, dealership just called and said the rear seal appears the be leaking again and they are concerned about the high oil pressure causing the leak. They are waiting to hear back from Chevy engineers before doing any work, although they think it has something to do with a pressure relief valve in the oil pump. I have read about this before, but everything I read was about the valve getting stuck and having no or low oil pressure, not high oil pressure.

So,,,,,,, my question now that I wrote a book… What could cause the high oil pressure????

[greenbullitt]

a sticking relief valve in the pump could cause th op issue, but I dont see that causing the rear seal issue

[Juiced4v]

Is the car still under fac warranty?

[shumpertdavid]

Had a customers vortech 350 hang up the,pressure relief valve in the,pump, it would blow the oil filter it made so much pressure. Lime Paul stated though, can't,see that causing,rear main to leak. It affected by crank case pressure, but not oil pressure that I've ever seen.

[Big A]

The relief valve sticking shut would be my first thought, but a blockage anywhere would net the same.

It could also be a bad oil pressure sender giving the gauge a false reading. Not common, but it happens. This would be preferred, and an easy fix when compared to the other possibilities.

[Lason]

Im 99.9% sure the pressure relief is in the block under the rear cover by the rear main seal, not in the pump. Remove the rear cover and its in the passenger side by the oil pan rail.

[Lason]

oh and food for thought, I googled pressure relief valve and ran across this. Seems there may be a TSB on it. http://www.camaro5.com/forums/showthread.php?t=72458

[Blackpony]

Most of the ls engines we do at the shop, we hotrod the oil pump thus giving more flow and higher oil pressure. Typically we see around 60 lbs of oil pressure once it is done. If the rear main was installed incorrectly, that will cause it to begin leaking again. Sometimes the seal will get pinched during installation.

[VaderTT]

Typically we see around 60 lbs of oil pressure once it is done.

@ what rpm? lol.

[Blackpony]

@ what rpm? lol.

It varies. Depends on mileage of the vehicle.

[03WhiteGT]

Is the car still under fac warranty?

Yep

[Nash B.]

It could also be a bad oil pressure sender giving the gauge a false reading. Not common, but it happens. This would be preferred, and an easy fix when compared to the other possibilities.

It wouldn't explain why the rear main seal keeps leaking though.

[greenbullitt]

sounds to me that you have 2 seperate problems, the rear main is NOT pressure fed. Hope they figure it out for you. What was the coolant temp when you saw this op reading?

[03WhiteGT]

sounds to me that you have 2 seperate problems, the rear main is NOT pressure fed. Hope they figure it out for you. What was the coolant temp when you saw this op reading?

Coolant ~198 and Oil ~225

[greenbullitt]

not temp related then