Disca said:
No clue where your information comes from but it certainly will affect diesels.
My clues and information comes from that I drive diesels sometimes up to 40k miles/year and drive them up to 300k miles without problems.
And so have many others for decades and decades. Carbon buildup has never been a real issue with these cars, not on the valves; only the egr valve sometimes does have issues if you don't floor your car once in a while... It's an elderly problem :lol:
If it's dirty it's still no problem. If you cleant it, it will be dirty again after 2k miles because of the oil from the ccv.
When it becomes really flow restricting, or very hard crud that restricts valvemovement, then it's a problem
It's like you see with a lot of products. As soon as they hit the market, it's suddenly an issue and everybody has that issue.
Mostly the peolple who do not take up the spanners themselves and have a guy for everything. Those people don't know what's normal and not normal in an engine. They are ignorant.
And the marketing of these products knows how to use that situation.
And my clue comes from that I sometimes remove an inlet manifold and swipe my finger over stuff.
Not from Aldi's though... everybody knows they're crap...

oke:
Anyway any engine that pollutes itself so much that every 30k miles the complete inlet manifold has to come off for walnut blasting (yes, that is what that garage wants us to believe, every 30.000 miles, without reservation!) is a really crappy engine in my book.