bimmereater

i've attached the letter Audi Canada provided in response to my concern over repeated problems with valve deposits. hopefully Audi will own up to the issue and provide a resolution.....

ArthurPE

wall-nut vs walnut shells lol

sounds like a bunch of double speak, placation and avoidance

citanest

I am from Toronto as well and I had the build-up problem at 22,000km. I went to Mississauga Audi and they took out the Manifold and manually cleaned the build-up, changed oil separate and few other things. Then flushed the engine with BG fogging system. I dynoed the car right after just to get a baseline and a reference for future. They car seemed to be running strong. My car is now at 28,000km and time will tell if it happens again. I will put a scope into the manifold to check the valves in November. Probably do another dyno as well.

Good luck with your car.

silverRS4

“Please understand that as the weather temperatures become hotter, the buildup has a tendency to worsen and can cause a loss of engine performance”

Wow, they do know something of the problem. They preach Tier 1 fuel, (supposedly for the detergents) then admit that the problem worsens in hot temperatures. Why? Because unburnt fuel is one source of deposits and the RS4 produces it in spades when the intake air temp is over 80F. Even with 93 octane, in normal North American summer weather (80F) the ECM's are retarding timing by 10-13 degrees. They make it sound as if the buildup is causing the power loss, but actually, the retarded timing is heavily responsible for both. The oil separator system is getting picked on as the "source" of the buildup. I was on that wagon. But after logging data through 4 seasons, I am starting to think that the separator system is not really faulty - hence, no urgency from Audi. Tier 1 fuel helps, but its an octane issue just as much as a detergent issue (although Audi is overly optimistic if they think proper detergents and an occasional fuel additive will "cure" the deposits and you'd need 96 octane to get no retardation in 80F temps in the RS4). The only time my valves have been fairly deposit free was in the dead of winter (very little, if any retardation occuring due to 0-20F temps). They had been cleaned by the dealer in November and remained fairly clean until March. Then after 5 months of warm temps and 10 degrees plus of retardation under load, (and all else being equal) I spent several hours cleaning my valves in August.

bimmereater

Queensway performed basically the same service, only after 4 o 5 visits did they actually take out the manifold and remove the deposits. this was all warrantied. however, i'm close to the expiration of the 80k warranty so the next time its going to cost $1500+. i'm already noticing a brief loss of power around 3k rpm during acceleration, but not sure if this is related.

I'm interested to learn what you find when you inspect your valves in november....

thanks for your comments.

ELEVENS

Very interesting, thanks for sharing the letter.