<center><img src="http://pictureposter.audiworld.com/39022/coolantleak.1.jpg"></center><p>After letting my car sit for the summer, I brought it into my garage and found the leak at this junction of the plastic inlet. The leak doesn't begin until the engine gets warm. What to do? The leak is too fast to drive the car to my Audi guy about 15 miles away. Is this something any willing garage should be able to fix? Could this leak be related to the aux water pump installation I had done just prior? The car also began running hotter after this even with coolant topped off--the fan isn't kicking on until the needle gets to the first small dot past the center of the gauge. Thanks for your help!

You were lucky to have some warning. Heater control valve comes apart while driving with catastrophic outcome. I get new plastic ones here in Toronto very cheap, or you guys in the US can also go with metal ones from Autozone, or Napa (not sure which chain it was). Do not drive the car until it has been replaced.
Zoran

I believe from your picture, that is your heater valve which when you select heat for inside your car it opens and allows hot water(antifeeze) to the heater core. You could remove the valve and insert a straight joiner until you get a new valve which sell for roughly $15 on Ebay.

You should be able to put a new one on in 15 min. Undo the two hose clamps in the picture. Disconnect the heater control valve from the coolant hoses and one vaccum hose. Coolant will flow out from the engine side. So install it quick. The valve is easy to find in parts stores and it costs something like $15.

This has nothing to do with the after run water pump.

The "over" heat could be bad thermo switch at the bottom of the radiator, cloged radiator or you have lost the 2nd stage of the radiator fan. After putting in a new heater valve, do the following test(I think audiqv8 posted this method first). Get the car to temperature, just before the fan kicks in, touch the upper and lower radiator hoses and feel the temperature difference. If they are equally hot, then you have a good radiator and most likely a bad thermo switch. To see if you have good 2nd stage fan working or not, visit SJM site.

Zhaoming

Thanks to all for your quick responses! I will pick up the part at AutoZone and give it a shot. My ol' Audi just bought a few more months of life (hopefully).

HEY, if this is so risky i better do mine, but where is it on the 5k?

Back of the block, look for coolant line that goes to a plastic pos looking thing that then has a line goin into the firewall(heatercore), easy swap, a little messy if your not quick. ;)

ty guys ;)