Can I replace my BMW engine top that is leaking oil?


What you need to know:

  • Silicone sealant is sometimes used to stop the leaks with varying success.

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. Although they should not be ignored, oil leaks around the engine valve cover do not warrant replacement of your engine. 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.


Does my van need water in the cooling system?

Hello Paul, I have just bought a Toyota Hiace van and I have a question. I see two coolant containers, one on the radiator and the other, a white container which is empty. Can I fill it with water? Nankunda

Hello Nankunda, the white container with a picture of a radiator on its cap is a coolant expansion tank. It should be topped up to the recommended level with engine coolant and not water. Reputable engine coolant is designed with additive molecules that prevent corrosion and overheating of the engine while lubricating fast-moving parts of the cooling system such as the water pump. 

I suggest you go to a garage or good service bay and carry out a comprehensive first service inspection since you have just received this used vehicle and may not have its service history. 

Start by building your own good service record of all serviceable fluids, filters, belts, hoses as well as ignition and fuel system components.
An inspection of tyre age and condition, lights, brakes, seatbelts and other safety or operational features is also necessary.