uneven engine idle?

[BerniniCaCO3]

Hi!

I have an uneven engine idle; maybe varies by 500 rpm every few seconds. Only in idle.

I've also had twice a short-lived oil pressure message. This was at speed; never at idle. Potentially a serious problem, I had a mechanic check, and the oil pressure was fine he said....
I've had a rare couple split-second flashes of the low-oil light, and I do mean split second. The oil level is full, and clean.

So probably the engine isn't getting quite enough oil, even though the measured pressure and oil levels read fine.

I was told I should change the engine filter. Would that alone be fair cause?
Also others hinted at the oil pan/ seals.
What does an "engine servicing" (is that just an oil change and filter...? or more?) tend to cost, if that's all it needs?

A neighbor suggested spark plugs?

The mechanic who first looked at the car and did my transmission work did notice the problem, but was just going to wait for a check engine light before he did anything. That hasn't come up yet.


Thoughts?


thanks!
-Bernard

[dpaton]

Motor type and mileage, when the Throttle Body was last serviced info., last time plugs were changed would help.


Plugs, air filter and TB are the easiest and cheapest to do and if they are correct then use the propane test to look for vacuum issues.

Does it run better if you run it with the oil fill cap off? Then look at the PCV system.

Have you run fuel injector cleaner though the system. Changed the fuel filter?

Turbo Control Valve can do this too.


On the oil side of things it's not likely a filter issue but either the pickup "O" rings or a faulty oil pressure sensor. First one requires dropping the pan, second is easier and cheaper as it is outside the motor.
http://volvoxc.com/resources/how-to/pdf/01-23-09/Oil%20Pressure%20Sensor.pdf
http://volvoxc.com/resources/how-to/pdf/01-23-09/Checking%20The%20Oil%20Pressure%20Sensor.pdf

[Willy]

Open the air box while the engine is running. If idle stabilizes, you have found the cause of the problem.
Willy

[BerniniCaCO3]

ah-- mechanic says a vacuum leak.
ACTUALLY, now that I think about it, several months ago the dealer said the engine o-rings needed replacing. Does that sound right?
But at the time, my mechanic (different from the one who said a vacuum leak) told me no, no, no; just the turbo seals, and so he did them; though it didn't change much.

Is the $800 for the o-rings that the dealer wanted fair? Well, I suspect not; but what price should I expect?

[dpaton]

Bump - Others on the forum have done that themselves - maybe someone can answer with part$ and time?

Change your title to include low oil pressure so the right people can read your post.

[martinperry]

o rings took me about 3 hours and £30 in parts