Originally Posted by BMWNTHZST
my wife's 335i has 51,000km and suffers from carbon build up too
Direct Injection is a crappy design
I'm scheduled for the walnut blast on Monday. My question is...moving forward what steps can I take to prevent this from happening again? Should I be using a product such as ZMAX every 5,000K ?
By the way I've always changed the oil in my car every 5,000K and I only put in Shell 91 gas.
There's not really anything you can do to prevent it. It's just something that happens in DI cars. Some people have said that they reduced the frequency of needing an intake valve cleaning after installing an oil catchcan, and running meth injection seems to help as well (but I doubt your wife would want to go that route
Gas or any fuel additives don't touch the intake valves in a DI engine, so adding anything to the gas tank does not do anything at all for carbon buildup.