Another engine overheating post... LOL! I dug around a bit on forums and couldn't find anyone that had the same experience. Here we go.

2012 A6 3.0T Prestige with 106k miles. I've had a slow coolant leak for around 2 years that I put off fixing for 2 years because it wasn't a big nuisance. Would get a low warning every handful of months, fill it up, and go about my day. Finally, back in June I actually had a CEL pop up and display warning about coolant overtemp. This turned out to be a water pump failure. Pull the SC and replace water pump, thermostat, Coolant Temp Sensor, crossover pipe, and coolant pipe that runs from front to back under SC and above PVC. Also, replaced spark plugs and air filter. End of June everything is back together and runs great.

Now, last Thursday (Sept 1st) I'm driving down the highway (~75mph) and I get an overtemp warning and I look and see engine temp has climbed up to the Red. I put it in neutral and planned to coast to the next exit. Before I can get there the temp drops back down to normal (right in the middle) and warning goes away. I put it back in gear and still plan on exiting to check things out. About 1 min later the same thing happens again. I put it in neutral, coast (this time down the exit ramp), and within ~30 sec the warning goes away and temp drops down to normal. I finally am in a parking lot and get out and check the coolant level to find zero drop in coolant. Don't see any evidence of anything really. Decide to drive it home (~5 miles back the other way) and had zero issues. Drove it yesterday (9/3) around town and again zero issues. Took a VAGCOM reading yesterday and attached the txt file (assuming that is the best way to post the VAGCOM log).

So, has anyone heard of or experienced this issue, and what was the fix? There are a few other Faults for ACC which failed a few months after I bought it (enter sad face) and misc things. What is new is the Boost pressure and MAP/MAF faults.