snagitseven

True. Post #17 made mention of a factory extended warranty letter re carbon valve cleaning and someone asked for details. So to clarify, I posted the only warranty letter that I'm aware of (and that I received from Audi) that addresses a related carbon issue which, of course, does not apply to the 4.2 engine or valves and injectors.

LLskier23

Thanks for all the info, Seven. Just too bad about what AoA decided to take responsibility for and what they left out.

Quefer

Well that's too bad. I will get the car back tomorrow and see exactly what they did. I have a 3.2. The only reason it fell under the extended warranty is b/c the CEL was due to carbon. The CEL had actually turned itself off prior to making appointment, but they were able to see it in the backgrounds. I hope the injectors got cleaned...

ajg617

I started tracking this after I purchased my 06 3.2. With 74K on it at purchase, I wondered what the value was of any fuel additive since I didn't know the driving habits of the previous owner. I drive my cars hard and red line them a few times a week, particularly when getting on the highway with nuts in front trying to merge at 30.

The local dealer does sell a VW/Audi fuel additive in a small 90ml can with a gray label. I asked the tech if it was of any use on a DFI and he said yes which I have to say I wondered about. But his instructions were to dump the can in the tank with about 10 gallons of gas in the tank and drive it hard for 60 miles. Then fill the tank.

Having run it through the gears full throttle before, I didn't notice anything out the back end before. But, after putting the VW additive in, I got a cloud of gray smoke like I couldn't believe. Granted this is likely post intake valve build-up, but I really was stunned.

jschrauwen

I've been remiss to look at other platforms besides my A5 on the topic of carbon build up on the 3.2L.
I picked up my 08 A5 3.2L (private sale) in May 2015 with 82k kms (~50k miles). After getting more familiar with the car I discovered the subject of carbon build up in the intake track/valves for the 3.2L and other FSI engines.
I've never encountered any of the normal symptoms associated with this issue (difficult cold starts, CEL's etc etc) but didn't want to take any chances. Last summer I took my car (at 98k kms) to a Euro specialist shop to have my intake valves inspected with the high likelihood of it needing a cleaning via walnut shell blasting when .
To my surprise, there was no significant carbon build up. I'm not sure if this can be attributed to the previous owner's (2) driving habits as one of them was literally an old lady. However, her son was an exotic car hobbiest/owner and was in chanrge of routine maintenance. Suffice to say, the car saw more frequent oil changes with quality oil and filters as presumable top gear gas was used. Maybe the PVC's were actually doing a better job then most others but it's hard to pinpoint the specific reasons.
n my defence, perhaps it's because of the frequent oil changes done (every 6k kms to 7k kms) or perhaps the type/style of driving I do (Italian tune-up every time I take the car out which is weekly or the predominant use which is 85% highway), but whatever it is, it appears to be staving off the absolute necessity for a physical carbon cleaning.

Someone posted that there's a regular servicing interval (55k miles) to replace the cam follower on the 3.2L V6? If this is the case, I have no records from previous owners of this being done. If this cam follower servicing info is indeed a normal scheduled requirement, then it seems prudent to have the walnut shell or soda blasting process done at the same time?

Here are a couple of pics of my intake valves taken last summer at ~ 98k kms.
https://www.audiworld.com/forums/att...1&d=1486836576
https://www.audiworld.com/forums/att...1&d=1486836576