My Oil Pressure.

[Captain Crunch]

Hi All,

My oil pressure at start up is at about 20-25 psi and slowly climbs to 40 psi as the engine comes up to operating temp, 150F. Everything stays steady at 40 psi and 150F while running at cruising or idle.

From what I have read oil pressure should start high and fall to 40 psi as the motor heats up.

I use 15-40 and change every 25 hours or so.

What does it mean when it does the reverse?

Thanks.

CC

[thatch]

"Think thick milkshake"

My theory on this phenomenon has to do with the A4's relatively small oil-pump intake fitting size. When the oil is cold, and at it's thickest, it cannot easily make it through this fitting preventing the pump from pressurizing the oil galleys like it can when the oil is warm and flowing more freely. Since you are able to reach 40 psi eventually, it would appear that your bearings are in good shape. Using 15-40 oil is probably contributing to this seemingly odd situation.
Tom

[roadnsky]

My oil pressure at start up is at about 20-25 psi and slowly climbs to 40 psi as the engine comes up to operating temp, 150F. Everything stays steady at 40 psi and 150F while running at cruising or idle.

CC-
Those are almost exactly my oil pressure numbers and scenario.

[Captain Crunch]

Sounds like...as long as you get to 40 psi your're generally good.

I guess about all you can do to service the system is re-seat the pressure valve and run MMO through it?

I've been putting about a cup in with the oil change that I do twice a season.

CC

[joe_db]

It doesn't sound like a big problem to me. FYI - I find Shell Rotella 15w40 to be a good oil, it seems better with oil pressure than some.

[Indy]

My oil pressure works it's way up to between 35-40 psi as the engine gains rpms and works under a load. Occasionally, it stays right at 40, but more often it is on 35. I have attributed this to the gauge honestly, being 43 years old. Maybe an oil filled gauge would be a little more accurate. At any rate, it's not been alarming to me.

[Boat]

CC-
Those are almost exactly my oil pressure numbers and scenario.

ditto here too.