I was wondering how many RS4 owners have experienced a decrease in performance (due to "carbon buildup"). I've been reading through posts on the various Audi forums, and this seems to be an issue with [some] RS4s.

I recently took possession of a 2007 RS4, which has received a carbon cleaning (using some sort of walnut spray) before my purchase. What is unclear to me is how often the carbon clean (which may cost ~$1500-$2000) is required?

From your experience, is it more of a yearly, or a >3 year cadence? It doesn't appear driving style is the cause of the problem, but I could be wrong.

Any insight appreciated.

Marcus.

 

While I have no specific knowledge of the 4.2's issues, carbon buildup is a problem that has been around since the advent of the internal combustion engine. It is most often attributed to driving a performance engine in a granny-esque manner, or poorly engineered emission systems. I would not be surprised to see many RS4 owners not winding their engines out regularly, or driving in relatively passive manner. Don't be afraid to rev to redline anytime after the oil is brought up to operating temperature; in fact, try to do it everyday!

FYI, the "walnut spray" likely means that it was pressure-blasted with walnut shell media. Google Italian tuneup for a cruder, but often efficacious, carbon-removal method

 

You may wish to tap into the US crowd where there are many more RS4 owners (AZ, AW, QW). It seems that driving behavior along with type of gas used has an impact on how quickly the buildup ocurrs. I was very happy with the power of the car prior to cleaning and even happier afterwards so perhaps its not worth worrying about until you either feel a loss of power OR have CEL's (and then hopefully the CPO may kick in). Cheeba is right about the walnut spraying and its Audi's approved method of cleaning. That said, others will do by hand using small "tools" to scrape away the buildup. Next time we see each other, I'll give you the before and after shots ...

 

Thanks for the info.

I found a really good link on the AZ site summarizing the RS4 Carbon Build-up concerns/issues. As a reference, it is "http://www.audizine.com/forum/showth...ad-for-RS4-4.2".

I'll monitor the situation. If it is a problem for my car, I hope that it does not result in any engine damage (as another RS4 owner that claimed the build-up damaged his piston). I can also live with a cleaning every once in a while, but every year would irritate me.

As a proactive step, it just means I'll have to wind her out very frequently. Ahhhh, the glass is half full after all. Now I have a rational reason for doing what I enjoying doing with that car. I can't wait to tell the gf "... Honey, driving the car like I stole it is a documented maintenance procedure..." Oh, she'll love that one.

At any rate, thanks for the advice gentlemen.

 

Seems to me she liked the sound of the exhaust at WOT so it should be an easy sell.