Hi y'all, I just bought a 2002 A6 Avant with 27K miles and BROWN coolant. I have many bottles of Pentosin G-12 to fix it, but I can't drain the old coolant.

The lower hose has a plastic fitting with a drain tap behind the radiator, but when I turn it 1/4 turn Counterclockwise, nothing drains, or drips. I have the expansion tank cap off, and engine warm.

Then I tried to remove the hose end from the radiator, I pulled the spring circlip UP 1/2 inch or so, to the stops in the fitting thinking that the o-ring seal would let it pop apart. It will not come off with wiggling or cussing [:@], and I don't want to break the plastic radiator.

So this is my 1st Audi since a cool 1958 DKW 3=6 many years ago, and I even have the Bentley manual on the A6, but it's not too helpful so far. So if anyone has ideas, Thanks.

Joe in Atlanta