I have a 2003 A4 1.8t auto. The temp guage is always slightly past the middle marker. I've always seen the marker square in the middle on other audis. I wasn't worried about it, but the car temp spikes randomly and gets very hot. My thermostat housing exploded and head warped after extreme heat a few weeks ago. I've replaced the head/gasket and the car is back to running slightly past middle on coolant temp guage, and I'm worried about to destruct again. Has anyone seen this problem. I'm hoping just air in cooling system? . I'm at a loss and don't want it to overheat again. The top hose gets hot and bottom radiator hose just warm. Any advise appreciated. Thanks

 

if there was air in the system, the needle will dip a little bit. but how far passed the line is it? it could be the needle is off a bit.

if you have access to vagcom you can do a gauge needle sweep which will end in the needles in the half way mark. <- this will tell you if its just the gauge its self.

if you drive with the heat on full/fan on full does the needle come down at all?

 

Thanks for reply.

The needle is just slightly past the mark, just enough to notice. I have a vagcom that has been reading too many errors to communicate...frustrating. what function do I use to check the needles? I'll see if it works. I have no heat to the heater core. When the head was off I ran compressed air through the core to try and dislodge anything. It blew coolant out. Do b6 cores bleed the same as b5, out of upper core hose?

I recently poured water into the upper radiator hose which poured immediately out the bottom hose, like it didn't run through the radiator. I was hoping the radiator was clogged (easy access) cause the upper hose gets hot and lower remains cool/warm. I definately have coolant flow problems, trying to determine water pump (brand new), thermostat (brand new), heater core or air in the system. can air cause no circulation?

At some poing this poor car had coolant leak stop ran through it. ugghh
Thanks again for any suggestions.

 

if you go to module 01-engine then hit output tests; the sequence is analog gaugle needle test. you must complete all output tests, so once you start juts click thru to the end after you did the needle test.

no heat is most likely due to blocked heatercore.

B6 has two bleeders. one is the screw cap on the pipe thats over the intake manifold, the second is if you look next to the battery, there is a pipe with a hole in it. you must move the pipe back until it starts coming out the hole.

and yes air can cause no circulation but this generally would happen if the air pocket was at the rear coolant flange.