Questions and Answers
BMW Engine Concerns
Q. Dear Vincent, I stumbled across your web site today and I hope its the answer to my prayers. I bought my 1991 BMW E36 320i manual 4 door saloon. 10 months ago when it had 109,000 miles on the clock. It has run beautifully ever since apart from two episodes when it refused to idle.
This was cured both times by resetting the engine management unit which appears to continuously show fault code C80. I also noticed recently that the air filter casing was open about an inch and had been for quite a while.
Last week at 135,000 miles the engine started running rough, producing a louder noise, vibration which is particularly noticeable through the accelerator pedal and hesitancy on acceleration. I had the garage look at it but they can find nothing apparently wrong. However I have now found that it is using a lot of oil, 1 litre in the last 200 miles. There is no obvious blue smoke but there is a faint smell of burnt oil from the exhaust at the end of a long trip.
I am worried that by continuing to drive the car I may be doing damage to the engine. Can you help with a possible diagnosis or point me in the right direction? I hope you have time to answer this one, and thanks in anticipation.
Jonathan
A. This is going to be difficult because this is a non-US model and the DTC's are different from the US models. I would love to know what the C80 code indicates.
If the air filter case was indeed open for an extended period of time, it is possible that dirt and other garbage got into the engine and possibly did some damage. I think we need to start with some basic tests to get at the root cause of the problem. Since you seem to be burning some oil, I would start with a wet/dry compression test. This will tell a lot about the basic condition of the engine and if the rings or seals are allowing oil to enter the combustion chambers.
I have a bad feeling that some damage was done to the internal parts of the engine, indicated by the noise and rough running. I think when you have the compression test done, you should prepare for the worst.
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