1995 BMW 525i engine problems

1995 BMW 525I
328,000 MILES • 6 CYL • 2WD • AUTOMATIC
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AGH
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Our car is emitting black smoke upon start up and runs rough. After it warms up the engine smooths out, but there is blue smoke coming out of the exhaust pipe. We are getting oil building up in the air fliter box. Over time the oil accumulates to about 1/8 "in the air filter box. Then the car begins to run rough. If we wipe out the air fliter box and get rid of the oil the car runs smooth again. The car has always been serviced with synthetic oil.
Can you tell us what is causing this and how it can be fixed?
Jan 14, 2010 at 9:49 PM
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DOCHAGERTY
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Black and blue smoke certainly indicate a problem. There is an intake manifold leak causing oil to pool in the airbox, that is very possibly where the blue smoke is coming from. Black smoke is running too rich of a mixture. The M-50 motor was not intended to run synthetic oil. BMW intended it to have 20w50. Get the intake checked for vacuum leaks, I usually use a smoke machine to find intake leakage.
Jan 15, 2010 at 9:01 AM