brider

I previously owned an allroad (2.7t) that I really liked, but have conceded that what I really need is just the quattro wagon configuration....so I've been looking at C6 A6 Avants.

Is there a dedicated thread or previous "white paper" on the likelihood of a 100k engine definitely requiring timing chain/tensioner/guide upgrades, or do some of these engines really last untouched?

Prospeeder

These engines in A6's are not VR6 engines. These are traditional V6's with chains on the rear of the engine. As far as the chain guide issues, seems any chain driven audi/vw engine needs new chains and guides somewhere between 100-160k miles.

The 24v Vr6 is in TT and Q7 cars. As well as Passats, Touregs ect...

LarryJa

Yes, the 3.2 fsi engines do have an issue with timing chain guides & tensioners, especially the upper chain tensioners. However, the upper tensioners can be replaced with the engine in place &, relatively, easily. They do, typically, last about 100-170k miles, originally.
It's, actually, an easier job than a timing belt replacement on earlier V6'so.
The only other recurring issue is intake valve carbon build up. This seems, to me, to be an issue more with cars that see less highway use. The carbon build up occurs because of the direct fuel injection not spraying raw fuel into the intake ports anymore. There's no fuel spray to clean the valves. So, over time, the valves build up carbon deposits. Manual hand intake ports & valve cleaning restores engine performance on this one. The frequency of this service is very variable, car to car.
Neither of these issues is a "game stopper". However, the fact that the 4.2 V8's require engine removal, for upper tensioner replacements, did convince me not to buy a higher mileage one of those.