This picture above shows BMW N20 engine from the F30 model. Performed a general complete engine overhaul after customer complained that the temperature was going rapidly high. After thorough checking and diagnosis we found out that the engine oil has been sludge. This is a common problem faced among owners of continental cars here in Malaysia the prime cause of this is due to the climate here which affects the temperature and viscosity of the engine oil and thus causes it to sludge.