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Old 12-19-2012, 04:06 PM
snowsled7 snowsled7 is offline
The Ornery Old Man
Location: SW Mountains
 
Join Date: Mar 2012
Posts: 980
Mein Auto: GTI
Quote:
Originally Posted by CurtSmall View Post
I haven't had this issue with my BMWs, but I had the exact same symptoms on a 93 Range Rover I used to drive. In my case, it was the main bearings on the crank. When the oil was cold, the oil pressure was above the sensor specs, but as it heated, the worn bearings could no longer maintain back pressure thru the journals in the crank. The engine had no knocks or noises to indicate worn mains.
Right but, that is on a Buick engine designed in the late forties.

To the OP...

This is really simple, the answer has been given and confirmed. Oil is thicker when cold, that is why it gets progressively worse. It takes almost 30 minutes of driving to fully warm your oil, especially in the winter. When the idle speed drops, the pressure warning light flickers because the pressure IS dropping. There is nothing wrong internally, there is a problem with getting the car to idle at the proper speed.

Fix the idle, fix the oil light.

So, clean and test the idle control valve, you can do this at home for free. Replace if necessary.

As mentioned the O2 sensor is a possibility for your rough running but I doubt it. Spark plugs, valve adjustment if applicable are some other cheap things to check.

So fix the leaks and get it running right, stop worrying about the oil light, it is a symptom, not the problem.
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Current ride... '13 GTI Wolfsburg
BMW's from my past...
'92 535i/5 '89 325ix/5
'98 750iL '86 325(e)/5
'95 740iL '84 318i/5
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