I have a 2001 Jetta Vr6, im not sure if its a 12v or 24v. my car wont overheat if i drive without the ac, unless its really hot out, but if i turn on my ac i can drive about 15 minutes or so on the street before it starts to overheat. the car wont overheat on the express way. i can have the ac full blast on the express way and not overheat which is weird. i do not see anything leaking. i checked the oil. it has antifreeze, but i still have no clue. if anyone can direct me as to what they think it is. its is highly appreciated. thank you in advance.