Does your engine also continue running for a short period after the engine has been switched off? This is called dieseling. This is can be caused by the pollution in the combustion chamber.
As a result of engine contamination, cabbage remains in the combustion chamber. Normally, light pollution does not have much impact on an engine, except for an slightly more consumption of oil and fuel. When the pollution increases in the combustion chamber, it is possible that the carbon residues will glow during driving.
When the carbon residues start to glow and gets an substantial heat, it is possible that the fuel explodes because of the heat from the carbon residues and not the spark plug. When you turn off the car, the remaining coals are still glowing and some explosions still take place in the combustion chambers.
The cabbage residues can cause a lot of damage, they can also provide for the pinging in the engine, read more here. Dieseling can also cause a lot of damage, because of the fact that the pistons are not in a position to handle an explosion.
One’s always better safe than sorry. Many cars on average do not drive more than 15km, and will probably never get high in the rpm. This is to ensure that the fuel consumption remains low, but the engine will pollute faster.
To optimally clean the combustion chamber, we recommend using Speed Cleaner and Top Engine Cleaner.