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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 212
Experience:  Mercedes Benz Qualified Diagnostic Technician
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My car was taken to the MOT and it failed but my main

Customer Question

My car was taken to the MOT and it failed but my main concern is there a blue smoke when the car is on neutral gear or when you are stop. It is also to higher, when you drive the car shake
Submitted: 16 days ago.
Category: Mercedes
Expert:  CarDoc replied 16 days ago.

Thank you for using JA. I'm Baz, one of the automotive experts, I try to be available in the afternoon on weekdays and in the evenings on the weekend. I apologise if I do not respond to your question promptly, I can assure you that I will respond as soon as I can. Thank you


Customer: replied 16 days ago.
What are suggesting we should do
Expert:  CarDoc replied 16 days ago.

Blue smoke indicates that the engine is burning oil so, oil is getting into or very close to the combustion chamber (inside the cylinders). The oil can get in past the piston rings or the valve stem seals.

I would recommend doing a compression test on all cylinders, this will tell you if there is an issue with the valves or pistons.

Customer: replied 16 days ago.
Can you not help me to do it. Because I don’t want to take my car to someone who is not a specialist
Expert:  CarDoc replied 16 days ago.

We can only advise on what you can do or get done at a garage. If you don't have any experience, I wouldn't recommend trying to tackle this job yourself.


Apologies, I can't take calls at the moment.

Expert:  CarDoc replied 16 days ago.

Any half decent garage should have the equipment to carry out a cylinder compression test.