Is it harmful for cars to dig coal?

Fuck, it doesn't hurt the car to be formal.

Coal mining is to clean up the carbon deposits in all aspects of the intake pipe of automobile engine, including intake valve, throttle valve and intake manifold.

Reminder: Coal mining is a job that requires professionalism and patience. It will not affect the sealing performance of the engine, but just in case, the owner still needs to find a regular garage.