Re: ([email protected])
The B5 chassis A4's have a number of potential known issues, some of which are covered in this thread.
As stated, control arms and ball joints will fail--not a question of if, but when. Look for records of replacement; otherwise, on cars with over 80k, factor it into your budget.
The dual-mass flywheels are known to fail, leading to a 'clunk' sound/feeling when you transition off throttle at freeway speed in particular. This becomes more evident if you install an uprated snub mount.
The oil sludging problem is not a small issue for the 1.8T's, and can potentially affect any of the older cars. Check to see if the car has been run with synthetic oil; if not, have it thoroughly inspected by a mechanic that is thoroughly versed in the sludging problem and knows how to spot problem areas.
Older 1.8T's should be upgraded to the newer timing belt and tensioner, as the older design units can fail. You do NOT want to rebuild a 20v head.
Avoid older cars with ko3 turbos if they have been chipped. Most chips will overspin the very small ko3, leading to increased backpressure and big temperature spikes. This may lead to premature turbo failure. Even certain unchipped cars work the ko3 very hard (Passat wagon AT, heavily loaded), so it's worth considering that turbo replacement may be in your future.
If so equipped, the dot matrix displays in the IP have pixel failure issues much like Saabs do. An annoyance, primarily, but is not especially cheap to fix.
Ignition control modules and coil packs can fail; I kept a spare of each in my A4 1.8T and had to install the new ICM on the roadside at one point. Simple replacement.
I enjoyed driving my A4, and I think they are a beautiful looking car--perhaps one of Audi's best designs ever. It was simply too troublesome for me.
