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2001 BMW 740iL

Question: knocking sound in the engine

Question

hurry, Albemarle, NC, September 21, 2010, 19:06
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 Rookie

I have a knocking sound in the engine which is steady as long as the car is running.Analysis shows #3 cylinder is faulty.Check engine light is on all the time.A mechanic said there is oil coming in to the spark plug.Help!!!!

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  • Medium-star Best Answer
    patrick mannion from Greg Solow's Engine Room, September 21, 2010, 20:01
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     Master

    Knocking sound is not good (shows signs of mechanical engine damage). You are told oil is getting into the cylinder and fouling the spark plug and the code stored is most likely misfire number 3 cylinder. A compression test and or cylinder leakage test may be needed but it sounds like some engine dis-assembly will be needed to determine the extent of the engine damage and repairs needed.

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    hurry, September 21, 2010, 20:06
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    Thanks for your response.Would it be cheaper to replace the engine?Please respond.Thanks again.

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  • Answer #2

    European Motorsports from European Motorsports, September 23, 2010, 14:17
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     Enthusiast

    Check for a loose spark plug on #3 first. They make a knocking noise & a miss when loose.

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