You don’t get a lot of carbon build up with modern fuels. I wouldn’t worry about it.Is there any fuel additive or treatment anyone would recommend that might reduce / eliminate carbon build up in engine?
you should see a change after the treatment. Reckon on using close to a litre of water over the period of the spraying. Not all at once! Keep pumping the trigger until you hear the car stumble a bit, let it clear, then start pumping again.I'll try that with the cold water and see how it goes. Is it just one single jet stream of water and leave it for a few weeks? Or should I see an improvement straight away?
Surely ALL alloy heads have hardened valve seat inserts?
(am I allowed to mention names / products?).