I have a 2008 B7 Avant w/stage 2 APR and 113,000mi. I have had the Thermostat's replaced 3 times in this car, 2 in the last 14mos. All indication is it's happened again 2 days ago. Car temp shot up while stopped, the smell of antifreeze, drove off to get water circulating and temp came down. Got home and found reservoir was almost empty followed by big wet spot after car cooled. Temp gauge remains at middle so I've just been topping off the reservoir until car can be serviced.

Fortunately my mechanic warranties his work so 1 of the last 2 was on warranty. Pretty confident he'll cover this on warranty as well however I'm more concerned with what could be the root cause of this? Any ideas.........tks?