so, i looked for this red valve everyone talks about to flush out the coolant, i can'tfind it. i took off the front grill vents and searched.. still can't find it.. what is the easiest way to flush out the coolant, or find this valve thingy. thanks

 

There should be a valve attached to the bottom of the radiator (usually behind and you have to get under the car to find)that you just pull then turn the **** to drain (make sure the filler cap is open also). Then run a couple gallons of distilled water through to help flush any remaining coolant out and then refill with the fresh G12 and more distill water.

 

If you look through your manual,
it stated audi OEM coolant from factory is permanent, which means does not need to be changed lifetime.

 

good luck with that one...