Why is my BMW engine top leaking oil, can I replace it?
Hello Paul, I have noticed that my BMW X5 3.0 litre has an oil spill around the engine and all the spark plugs have oil on them. A friend has advised me to buy a used engine as this one looks messy. What is your take? Bob
Hello Bob, your BMW engine top cover or valve cover seal and spark plug seals are leaking engine oil and may need replacing. This is common when engines exceed 100,000kms. Engine oil leaks around the engine valve cover do not warrant replacement of your engine.
At the same time, they should not be ignored. Besides messing up your drive and affecting the oil level, oil leaks can also lead to damage of electrical components around the engine such as spark plugs, throttle units, harness sockets or the alternator.
When an engine runs, it builds oil pressure which is pumped from the bottom of the engine to the top to lubricate, protect and enhance performance of fast moving metallic components. Overtime, engine seals will warp and develop leaks due to heat exposure. When leaks develop, you ought to find a suitable mechanic to replace the old seals with quality new products.
Silicone sealant is sometimes used to stop the leaks with varying success. A slight change in engine oil type to a reputable mono grade with enhanced sealing properties can slow the progression of oil leaks. However, the use of heavier mono grade oils may not be applicable on your X5 which ought to have multi grade or fully synthetic engine oils as recommended by BMW.
