So, I have a 03 a4 1.8t, I had the check engine light code checked and it said the coolant temp sensor was bad, then the thermostat housing blew apart. So I replaced them along with the coolant flange. The car ran great minus a cracked vacuum line check valve. One week after doing the flange the car is now overheating. there is no coolant loss, all the hoses and ratiator are getting hot and i have tried to burp the coolant to see if there was just air in the lines. Im at a loss, im getting the check valve and the other sensor at the front side under the engine tomorrow, any thoughts to what else it might be? Plus i have had the water pump replaced to one with a metal impeller. like i said im at a loss.

 

u said u opened the coolant tank after warming the car up to get rid of bubbles right. Sometimes that bleeder screw wont get all the system clear. Just checking to see how u went about burping the system.

 

I opened the bleeder screw and removed the reserve tank bolt, then lifted the tank till only coolant came out of the bleeder screw. lol now im in need of a new bleeder screw as the old ones head popped off. I have a temporary blot in its place for noe but have one on order from audi as i couldnt find one online.

 

Ok so now with the new srcew in it will still overheat but if i turn on the heater it cools down.