I just bought my '03 A4, used of course. I have driven it for several hours continuously on the interstate, and have been driving it in the city for several days now, and have had no engine temp. issues. This morning, I had a short, 5 mile ride in traffic on the interstate, then i had to sit in line to go through a security checkpoint for about 6 minutes. The car ran and idled fine, however when I was about to leave the checkpoint, my coolant warning came on and I noticed the temp. gauge was about 3/4 of the way to the HOT line, when it normally hangs around the 1/2 way mark. I checked the coolant, and the expansion tank was filled to right where it should be. I got back in the car, the light went off, and the temp. went back down to normal? Anyone have any idea what this might be? If i take it to an autozone or somewhere, could there computer pick up a problem?

 

well the reason it went back to normal is cold air blowing into your engine bay lowering your temperatures. And when it was sitting there was no air going through which made it spike. As for it being normal no its not. I would change the fluid and/or flush the radiator with a garden hose.

 

what engine is it?

 

Changing fluid and/or flushing the radiator won't do anythingto improveairflow through the radiator. Check to see that your fans are operating correctly.

 

Clearly, it's an '03 A4 1.8T.

 

if it was the fans, wouldn't the car run hot on the interstate when im moving at faster speeds too? It only did it for a second that dropped back down to normal.

 

No. The fans are only effective at moving air through the radiator at low speeds or at a stop. At interstate speeds all the airflow is generated by the car physically moving through the air. If it runs normal at speed, but overheats when it's not moving, it's a problem with your fans.

 

If i take it to an autozone or somewhere and have them hook up their reader to the onboard computer, can that pick up an issue with the fans?

 

Possibly. I'm not sure how the fans are tied in with the computer, or if they are at all. The fans are quite loud when their energized, so if your car is not moving and is at or slightly above normal operating temperature, you'll definitely hear them kick in. If you don't, then it's either a faulty fan or something to do with the circuit controlling them. This is where I get fuzzy, as I know a lot more about BMWs. On the BMW, there was a sensor that controlled fan speed based on coolant temperature. I'd assume Audis function similarly, but I don't have details. There's probably a fuse for them as well, and being the easiest fix, that's what I'd check first.

 

Ok thanks. You've been a lot of help, your a smart car guy.