billychaos

I recently had my radiator replaced in my 2005 Audi TT. After that I noticed the temperature gauge going up when in on the highway. Eventually, the air conditioner started blowing hot air because it was shutting off due to overheating (this was told to me by the mechanic). The mechanic is unsure what is causing the overheating. After a few Google searches, I found that it could be that there may be air in the radiator causing it to overheat. To me that sounds likely but i'm not sure. It was previously checked for leaks after the radiator was replaced and it passed the tests. What would most likely cause my car to overheat like this?

dh53

I have emptied and refilled the radiator twice so far on my TT and both times had significant amounts of air trapped in the system that led to elevated temperatures on the first drive. I hope that all it is for you.

When the coolant is changed I warm up the car with the coolant overflow open and add coolant/water mix as needed for about 5 minutes then let it cool down. After that I take it for a short drive until the temperature reaches the normal operating point and stop someplace I can let it cool down again, then it always needs more coolant/water. After 1 or 2 of these cycles the air burps out and the cooling system works fine. The manual says you should always use a special vacuum tool to get the air out before driving but I don't have that tool.