I have an '04 A8L with 53k on it and suddenly I have a leak (unknown origin) and a temp gauge pegging on hot. Any thoughts on possible cause would be appreciated. Am getting crazy expensive estimates......first Audi, loving it but still learning . Thanks!

 

Obviously the first priority is to find the leak and fix it. You might be able to rent a pressure tester that will put a lot of pressure on your cooling system, forcing coolant out in the weakest point (the leak).
Just be sure to have enough fluid in the radiator and tank at all times so you won't blow a head gasket due to overheating.
Check all hoses, the bottom of the expansion tank, thermostat, and basically where all the hoses connect.
Does your car smell "funny" when you use the heater? If so you may have a bad heater core.

 

Thanks! Apreciate the insight

 

We found a coolant leak on a buddy's car by popping the overflow line off the reservoir, plugging the reservoir nipple, and putting my air compressor blowgun into the hose and letting 'er rip. Found the leaking hose in no time at all.