Hi i have a mercedes C180 K sports coupe! Had all four cylinders compression tested and all at 225 psi! No problems with the engine? But when i take the oil cap it breathes heavy! Mercedes of grims?? say thats the way the engines are! But this engine keeps creating oil leaks is this due to the pressurisation of the engine or the garage not doing the job right? If anyone has this type of car or the same engine (1.8 supercharged 4 cylinder engine w203) could you please compare for me, or anyone else who has any idea? Many thanks

 

Hi Madlions,

All modern engines develop some by-pass over the piston seals, especially turbo and supercharged models. Its not isolated to MB.

BUT all modern engines also have a system to vent this pressure out similar to a PCV system. MB has their own system that actually circulates air over the valve springs and through the block then out. They call it something else. If the vent, hoses, passages, or any actuators are stuck, you will build-up pressure, and this has been known to blow seals. I think your problem lies in one of these actuators, hoses, or valves. It sounds like you may be fixing the leaks but not fixing the actual cause.

The actuators can be tested with a $50 vacuum pump, and the valves can be tested with a 9volt battery. You can check your own hoses. You need to KNOW that these are working.

Charles