I want to change the thermostat in my 2001 Audi A3 8L1 1.9L myself, but I don't know which one to buy. I went on my local dealer's website, punched in my vehicle information, and I got a few thermostat results from different manufacturers. They all have the same temperature info, but vary in size.
Since I don't have any technical specs for my car or anything like that, how would I go about choosing the right one?