This oil pressure seems real low. Is it?

Zach Nelson · September 29, 2020

So I'm looking at a 2007 yukon denali 6.2L possibly to purchase. All in all seems solid except for the oil pressure seems really low at idle. I know these dash gauges aren't the most reliable but this seems concerning. 6.2L guys what say you?

CamGTP · September 29, 2020

If that is accurate, it's pretty low.

The lowest my 2012 ever got was around 20psi hot in the summer and that isn't even at the first line which is 20psi. That's like 10psi if it's correct.

Ideally you'd test it with a manual pressure gauge to confirm. If the manual gauge is higher then it's probably a sensor issue.

Zach Nelson · September 29, 2020

3 minutes ago, CamGTP said:

If that is accurate, it's pretty low.

The lowest my 2012 ever got was around 20psi hot in the summer and that isn't even at the first line which is 20psi. That's like 10psi if it's correct.

Ideally you'd test it with a manual pressure gauge to confirm. If the manual gauge is higher then it's probably a sensor issue.

Thanks for the quick reply! We are taking it to a 3rd party mechanic for them to go over it tomorrow. We will make sure they check it with a manual gauge.

Mike GMC · September 29, 2020

Oil brand and weight as well as filter choice can effect pressure. Do you know what's in it?

Zach Nelson · September 29, 2020

1 minute ago, Mike GMC said:

Oil brand and weight as well as filter choice can effect pressure. Do you know what's in it?

Unfortunately not at the moment. I will inquire tommorow

PPK · September 29, 2020

my 2005 yukon had similar pressure at idle in really hot weather. what happened was it used a little oil... and what i suspect is that my wife let it get down there where it was either way hot - because it had two quarts in it - or the engine was coming apart anyway. i never tore it down.. but it was in that period where the GM engines were pretty noisy - especially when they were cold...

Zach Nelson · September 30, 2020

Actually found the oil info, forgot we got service paperwork from them. 5W30 motorcraft oil. Oil filter is part number R84060. Doesn't mention brand but google search brings up Carquest

15SilvyHC · September 30, 2020

So I've been reading up on this and it would seem the oil pressure at hot idle should be around 20-25 psi.

IF testing manually with another gauge confirms this vehicle is only at about 10lbs I think it would be safe to say this is a vehicle I should stay far away from correct?

It seems likely it would be a oil pump going South or worn cranks bearings if it isn't the 'easy' fix of a new sensor. Or possibly O-Ring around the pickup tube leaking but that requires the pan being dropped.

Any other possible 'easy' fixes? I know I could run some thicker oil in it and who knows it may run for years but I want something mechanically sound not something with a bandaid on it.

The dealership didn't seem to want any part of addressing the issue yesterday. I guess they figure someone will miss the issue and buy it. I'm not looking at pouring a lot of money into repairs. In the end I will probably just end up walking but maybe dealership will come around and fix it.

I am the same person as the OP. Just realized this is a different account.

PPK · September 30, 2020

well like any used vehicle.. check the tail pipe for signs of oil seeping past rings and valve seals... listen... hard at how much noise the engine emits - piston slap - rod or main knocks.. on start-up, when it is cold and warmed up.. check the radiator for coolant.. and bubbles... on and on.. low oil pressure might be a red flag and might not be.. you have to look and listen..

Donstar · September 30, 2020

15 hours ago, Zach Nelson said:

Thanks for the quick reply! We are taking it to a 3rd party mechanic for them to go over it tomorrow.

Good plan. This vehicle has good mileage for its age but it is still a well used vehicle with aging parts. Plan for potentially costly repairs and make sure the purchase price makes such repairs tolerable. No matter how carefully you scrutinize a vehicle, new or used, it can still give you unwanted surprises.

bshort · September 30, 2020

We had a Tahoe at work that had low oil pressure. It would have random AFM issues as well and the recommendation was a new engine. I would stay away from this one.

15SilvyHC · October 1, 2020

Well after talking with the dealer some more yesterday they have agreed to put a new oil pressure sensor on the vehicle and see if that resolves the issue. They stated they would not be going any further than that however. After talking to a couple of mechanics and reading up on the symptoms typically seen with a faulty oil pressure sensor I'm not optimistic this will fix it. We did take it to a 3rd party mechanic but he said it would be $150 to do the test with a manual gauge so we decided against that when the dealer should be handling it.

Looks like we will end up having to walk away. A real shame because for a 2007 this vehicle was super clean and everything appeared to be in excellent condition other than that. Oh well the search continues I guess.

Edited October 1, 2020 by 03pewterZ