I have about 90k miles on this car and we were driving (mostly uphill when this issue occured) in the mountains this afternoon and began to overheat. It was ridiculously hot today, about 104 on the cars exterior temp gauge, and Denver set a record high per tonights news. Cars were literally lining the highway, pulled over, most likely for the same reason.

Temp gauge was about 3/4th's of the dial (pointing to about 2 o'clock) when we pulled off and popped the hood. Coolant began shooting out the back/bottom of the reservoir, and I'm not sure if that was the overflow valve doing it's job or something is really wrong there. The odd (aka, SCARY) part was that the oil symbol flashed on the dash board a couple times. That's what first made me pull over. Let the car cool down for a bit then drove home (about a half hour) and the temp stayed at 12 noon on the gauge thankfully.

Now, the car easily hits 12 o'clock on the temp gauge. I just drove only a couple miles and it was only 85 out, at night here, and the temp gauge typically used to only get to less than the half way (12 o'clock).

Is it the thermostat possibly? I went and bought one, but is replacing it really a job that entails removing the front bumper as another post suggests? I can't seem to locate it, looking down from the top of the engine. I hope I don't need to pull the bumper for a freakin t-stat. What else could it be?

I had the full timing belt job done at about 70k, which was about 14 months ago (I don't drive much working from home), by an Audi mechanic, including the thermostat I think. I also had the coolant flushed and filled by him (using G12 of course). I recently looked under the hood a few months ago and the coolant seemed a bit low so I topped it off, again w/ Audi G12. I MIGHT have topped it off a quarter inch over the max line. Would that matter? Was it purging excess coolant when I pulled over? What does the oil light have to do with it? There's no coolant drip on my garage floor or anything. The oil temp gauge never got too high (only about 1/3rd of the dial as it normally is). But there is an extremely small, like one small drip seemingly every month or so... doesn't seem major.

Any help would be super appreciated! Could it simply have been the extreme temps? I was only hitting about 4500 rpm max, not driving crazy, but it downshifts to get up the steep inclines. Ask me any questions you like to help get to the bottom of this. Thanks in advance my fellow Audi lovers!

 

You need to first find out for sure what he replaced. Find out if he used quality german parts, metal water pump impeller. It looks like you might need to redo the timing belt job.

Also if any of this is electrical such as a coolant sensor it could save you money and WILL/SHOULD throw a code. Get the car vagcom'ed for codes before you redo the timing belt.

 

Check water pump, and you may have a leak in your coolant expansion tank, so check that too.