Driving to work yesterday, my 04' Audi A4 1.8T started flashing Low Coolant and my temp gauge went all the way to hot. I was only like 2 blocks away from work, so I was just hoping to get there before I had to pull over. When I pulled in my work parking lot, my temp gauge went back to normal and coolant light went off?? So later on the night I went out to the parking lot with some water(because I have no G12 on hand) and I wasn't even really low on my coolant? It was at the min line, so I filled it up to full. Driving back home from work (35 minute drive) It would do the same thing then go back to normal, about 3 times it did that. I got home check out my coolant and it was back to min level again and I filled it back up to full. My fan was working/ my engine seem to be not overheating at all. I see where the sensor is (directly under the coolant tank) so I figured that wouldn't register until the coolant tank was empty? Kind of boggled! But also not a mechanic by any means, just know the basics. Can you please help!

 

sounds like a sticking thermostat. might wanna check it out

 

I have an 03 1.8 turbo a4 with the same problem, had it checked out today at pep boys, was told a head gasket was blown, repair cost $2300-$2600. I had a new thermostat housing and thermostat put in a out a month ago, any one please helps both.

 

It could be a bad head gasket, but before getting all worked up, do a compression and a leak down test.