i replaced the coolant flange of my 2003 A4 1.8T and it was a struggle. i made sure there was no air in the system and it is still overheating.

the car has never overheated before. i think it might be the thermostat not letting coolant through but i am not sure. does anyone know where i should start?

the upper hose is hot, and the lower hose is cold as ice. i dont get it.

please help

 

thermostat

 

I own a 2003 A4 and it recently started overheating, took it to the dealership and they're saying it's the flange.
First of all, am I an idiot for taking this thing to the dealer? Anyone else recently had this problem? Typical cost for repair? I've read a couple things online and this problem almost seemed typical at 60,000-65,000 miles, which oddly enough is right where I'm at. Is this as common as I think?

 

In my experience, the dealership has been the most knowledgeable place to take my car to, and when they have done work, they didn't break anything else. I recently replaced the flange on my car on my own, and it was a pita. If you are comfortable working on the car, it is doable, but there are a lot of parts you need to take off to get to it.

I would also have to say the thermostat. I recently had mine replaced, as well as the coolant fans (today as a matter of fact). I noticed over the past few days of driving before it was repaired, that when I pulled over and it overheated, there would be a lot of pressure in the coolant system, and the radiator would be bone cold. Replacing the thermostat is a fairly simple project as well.

 

I would try replacing the thermostat. Take the old one out and boil it in water on the stove and watch and see if it opens. This is a fairly easy part to check. If the thermostat opens cool it down and boil it again. Sometimes they stick closed and do not open. Good luck.
Anthonyz
Tony@zippyoil.com