Why does an engine need to be carbon cleaned?
Vintage Cars
It used to be the case that Vintage cars would need to be 'decoked' regularly involving opening up the engine and scraping off the carbon deposits by hand.
With modern fuels and technology, this is no longer necessary. However, engines can still need a carbon clean.
Sooty Exhausts
Engines receive power by burning fuel. Burning petrol or diesel fuel creates sooty exhaust emissions.
These emissions can be reduced by catalysts and diesle particulate filters, but some of it still gets deposited on parts of the inside of your engine and exhaust system.
Coking Up
Petrol is quite good at cleaning engine components on its way past making petrol engines less susceptible to ‘coking up’.
However, modern fuel injection engines prevent petrol from getting passed over as many engine components.
This can lead to some engines becoming clogged.
Diesel Engines
Diesel doesn't burn cleanly and so affects the engine more.
When exhaust gases are reburned when fed back into the combustion chamber the movement of sooty fumes results in a build-up of carbon deposits over time in your dpf and your catalyst.