So my Suburban is getting elderly and as such it has some GM problems. The latest one is oil pressure, it's low when cold. Winter start and gentle drive: oil pressure will show about 20 until it warms up and pressure rises to an indicated 40-45. Idle is a bit lower and makes me nervous (might be as low as 8-10 psi when cold, comes up to 20 when warmed up)
It's a 2004 Suburban with a 2006 motor that has approximately 120k miles on it. 6.0 LQ4 or LQ9 I believe.
What to do, run thicker oil? Thinner oil? Magic oil additive? Ignore it? Pay the man to replace the oil pump/pick up o-ring? I'd like to not have to replace the motor, it's my tow pig kid hauler.
What oil are you using now? Has it been a gradual decline or just much worse one day? Have you verified with a mechanical gauge?
It's odd that you have lower oil pressure when cold than when warm, that it backwards. Try replacing the gauge sending unit or verify with another gauge. Given your symptoms I would look at replacing the pickup o-ring but replacing the whole pump is likely not a bad idea.
At warm idle with a high volume Melling pump and 15w40 my car runs about 30-35psi.
Replace the oil pump pickup oring yet?
Cold oil pressure should be higher than warm. I have no answer other than change the oil pump.
I had a leak at the sending unit (and the unit itself was faulty) on my '89 C1500 that resulted in symptoms similar to yours. As Patientzero suggested, I'd start by validating the numbers you're seeing at the gauge, and then go from there.
Remove oil pan, replace pickup O-ring and oil pan gasket.
Pete. (l33t FS) said:
Remove oil pan, replace pickup O-ring and oil pan gasket.
If you're careful, reuse the oil pan gasket as it's a perma-oring deal. It's reusable.
Ranger50 said:
Pete. (l33t FS) said:
Remove oil pan, replace pickup O-ring and oil pan gasket.
If you're careful, reuse the oil pan gasket as it's a perma-oring deal. It's reusable.
At 120k it is getting ready to fail, though, and start leaking oil under pressure out above the filter housing.
In reply to Pete. (l33t FS) :
Leaking above the filter is the 2 bolt oil feed block off plate gasket has failed.
They tend to go at about the same time. For whatever reason the oil pan gaskets turn to jelly right there, and at the very front.
At the passages, where all the heat is, I understand, but the front?
In reply to Pete. (l33t FS) :
Oil pump.
In reply to Ranger50 :
That.... makes a lot of sense, actually, because a lot of the heat in the oil comes from the pump itself, so the pump's got to be radiating a lot of heat.
