[OUGrad05]

Guys, I was curious when carbon buildup becomes noticeable on the N55? Does it cause a loss in power, decreased efficiency etc? I would guess that at some point being a DI motor that it will. I know you can get the heads blasted at a dealer or indy shop. This isn't an issue I've encountered.

However, a friend of mine is considering the purchase of an N55 car and he Brough up the fact that this car has 85,000 miles on it and he's thinking it's probably got some carbon issues. It seems to run fine, he's going to bring it by tomorrow (he has it for the weekend) and I'll see if I notice anything out of the ordinary.

His question got me thinking about it though since I'm now at 55,000 miles. Anything preventative I can or should do? Or if he buys this one that he should do? I would assume running them harder actually helps with the buildup, but I don't run mine very hard...

Any thoughts or recommendations?

[n55david]

They dont have the same issues that the n54 had. Doesnt seem to be an issue.

[F32Fleet]

IIRC @ 100k miles the valves should be inspected.

[e38740imd]

correct. @55k i wouldnt worry about it. @100k then i would have an inspection done

[xnick101]

My friend is a BMW master technician and he says they don't do walnut blasting on N55's at their dealer atleast. The N55's are pretty efficient and don't need it. He said they do it only if the customer specifically asks for it.

[F32Fleet]

Originally Posted by xnick101

My friend is a BMW master technician and he says they don't do walnut blasting on N55's at their dealer atleast. The N55's are pretty efficient and don't need it. He said they do it only if the customer specifically asks for it.

Makes sense since I doubt they have too many customers with 100k mile or more

[Nickodarius]

All direct injections engines will probably need to have this service at some point. Engine efficiency has nothing to do with carbon build up on the valves.