What problems could I expect to have if I left my 2000 Audi A6 4.2L Quattro just sitting in an uncovered lot in the pacific NW for 3 years without being driven/started but has had a complete tune up and a new battery installed right before?

 

3 years?!?

well, the list of issues is most likely going to be long and distinguished. First, new battery or not, I expect it to be dead. putting it on a good battery conditioner for a few hours may bring it back to life.

next, your fuel is going to be all watery. it will need to be drained and replaced. after that, you are probably looking at having to replace all your other fluids as well, prior to even trying to start the car.

all the belts and hoses will need to be inspected. it is easy to assume that they will be ok because there has been zero "wear and tear". that, however, would be a mistake. those parts are designed to be "exercised" regularly. when they are not, things tend to rot, especially when left "exposed". in addition, all the "bits" that the belts drive will need to be checked to ensure that they haven't seized. again, keeping the bits moving makes them easier to move. allowing them to sit stationary for too long sort of invites them to decay to the point of permanent stationaryness.

if I were interested in ensuring that the car didn't self destruct when I tried to start it, I would have it taken to a reputable shop to have all the issues I mentioned (and anything I missed) checked out. If I was feeling adventurous and really wasn't worried about potentially destroying the car, I might just check the fluids and give a shot to see what happens.

good luck