jazzmegood

<center><img src="http://www.usatcorp.com/pics/car2.JPG"></center><p>Also posted this in the 4.2 V8 forum, but figured I might have some luck posting it here as well.

Bought an '02 A8L a few months ago with 60K. Now has 65K. Great car, and I was able to troubleshoot and fix the seemingly common vacuum hose breakage that caused the CEL light to come on. Thanks to Vag-Com for helping me fix this without a trip to the dealer. Considering that I'm by no means a mechanic, I was impressed. However, now I've got a new problem.

About 2 weeks ago, I happened to look at the temp guage while driving to work on the interstate and noticed that it was above it's "normal tickmark" as I call it, the one located about 1/3 the way up the guage. This was the first time I'd EVER seen it above that mark.

I thought nothing of it, but started watching it more closely. Over the next couple days, it started getting a little higher, and within 3 days or so, it was at the halfway point of the dial when driving at full speed.

I checked the coolant which was a little bit above the minimum mark on the reservoir. I topped it off to the max mark, hoping that might solve the problem. Unfortunately, it didn't. This past weekend, I visited some friends out of town, about 250 miles away. I noticed at one point that the temp climbed up to the 2/3 tickmark and stayed steady there.

Since I had the AC on, I decided to turn the heat on full blast to see if that would change things and it did. The temp fell back down, almost all the way to the "normal tickmark". After seeing this, I turned off the heat, but also did not turn the AC back on. I rolled down the windows and drove the rest of the way with the guage steady at about the halfway point.

This morning's drive to work was much of the same, with the guage reaching almost the 2/3 tickmark before I turned off the AC. This time, even with the AC off, it still stayed steady at 2/3, although I was near the end of the drive, so it may not have had time to start coming down. When I got to work, I left the car running and checked under the hood. The electrical fan and the belt-driven fan I could see were running. I also noticed that the coolant reservoir was sitting at max, which struck me as a bit odd. I'm by no means a mechanic, but I would think an engine running at 2/3 the way towards Hot would have pulled more coolant into the engine, therefore leaving the reservoir lower than max point. I may be totally wrong on this however.

That's basically it. The CEL light isn't on, but I will check Vag-Com tonight to see if it shows any codes. My only thoughts are that it could be:

Stuck thermostat
Air pocket in cooling system
Water Pump

Anyone have any suggestions, or experienced this before? Is it safe to drive the car with the guage at the 2/3 mark, or am I damaging the engine and need to put it in the shop right away?

Thanks for any info you may have.

PaulW

Very common failure mode on the 5v motors.....you probably want to do the timing belt while in there, then you'll be good to go for a long time.

A8CT

Unfortunatley, it's behind the timing belt and a BIG job to replace.

QuickA8

resolve to coolant spew.

skiracer1313

Yep, that's what happened to my '02 S8. Do as PaulW says - good luck!

deml0

same situation happened to me, and i ended up doing the tb service.

NODES

had the same issue on a different car, it turned out to be a stuck thermostat

tehA8PIMP

I did my belts and tstat 2 years ago/ 50k miles ago on my 99 A8q , and I still notice hi temps on the guage on hot days. First time I noticed, I was in a gas station filling up. If I still own the car next summer, I might flush the coolant(been 2.5 years) to see if that helps.

PaulW

Pre facelift cars, it's normally the mechanical clutch on the main fan

tozoM8

I've heard that is just nuts.
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