Thinking about purchasing my first Audi. What are some common problems with the B6? Looking at 1.8t, Quattro, manual, wagon. What should I look for before purchasing? Any info would be great. Thanks beforehand.

 

While I own a 3.O Quattro MT sedan, I know one major issue with the 1.8t's is oil sludging. Make sure the previous owner changed the oil on a regular basis and used synthetic oil. The state of the turbo would also be a concern of mine. Definitely get it checked out thoroughly by a good Audi specific shop prior to purchasing.

 

Ditto on getting it checked by a mechanic. If not, check maintenance items to see if timing blet was replaced and when. I bought a 1.8 earlier this year with 110K miles and never had tbelt replaced. I did the job myself. It took two full days to do. For me there was also issue with leaking coolant overflow container, cracked pcv valve (below intake manifold), worn out snub and motor mounts, and the oil was grummy looking.
I did all of those items above when I did the tbelt and water pump replacement, and have changed the oil twice in past 5 months to get rid of the gunky looking oil. The car runs really smooth now. I am using Lubro Moly 5W-40 (southern CA), and Mann (Large) oil filter and K&N Air filter. I have put 5K on the car so far and I love the car. The turbo wastegate stutters a bit so I am going to replace with either Garrett or K04 hybrid and do the 550cc Bosch injectors, and Moteza Stage 2 tune at the same time.
Not sure what price range you are looking, but I paid $6200 for mine (Quattro 5 Speed manual with sport & premium packages, not avant) and have put less than $1,000 into it so far, but plan to put about $2,500 in by end of year. For under $10K I will have a 240HP/270TQ car that I love to drive everyday, and that I love more than other cars I owned that I paid 3 and 4 times that amount for (had a Lincoln LS, Lincoln Aviator & Jag S-Type in past 15 years that don't come close to the pleasure I get out of my little A4.
Not sure if you are handy with tools, but if so, get yourself the Bentley manual, and search on here and Audizine for the maintenance item you need to do, and there will be tons of info on how to do it. The Tbelt job was a bear, as I removed the whole front end of the car to do it, but I learned SO MUCH on how the car is put together, and how it works by replacing it, along with all those other parts (and more) that I did that weekend. I am not a wrench head by any means but the instructions online and the Bentley manual gave me all the support I needed to get the job done.
Good luck!

 

I have a 04 1.8t CVT with 142000miles I bought it 4 years ago with 97k. Here is what I have done to mine in the last 4 years

-Audi changed all 4 coil packs for free
-had coolant flange, timing belt, valve cover gaskets changed right after purchase
-catalytic converter changed
-fuel filter changed
-CVT oil changed
-brake pads all around
-MAF changed
-spark plugs changed
-Motor mounts changed
-passenger side CV joint changed (driver side very soon)
-fuel pump noisy at start up ( even after the filter was changed, gonna need a new pump soon)

Most of these items were all maintenance. If you are handy with a ratchet you can do all of these things yourself. I havnt had any major issues as of yet. I will say that if you dont do the repairs yourself, its gonna rape your wallet! I keep the oil changed religiously every 5k with Mobile 1 0w-40. Hope this was helpful and good luck!!