Just an FYI - I have a 1997 A4 2.8L V6 FWD. - Replaced the coolant hoses to the oil cooler last week. Needed to add additional coolant and bleed the system again. Before I used the heater hose to do this. But this time I finally found the bleeder valve on the coolant pipe ( for some reason I could not see it before???). Here is a pic of where it is on my car.