First try changing the o-ring on the lower (leaking) heater core hose. I just did this job - New Coolant Flange, Upper Short Hose from flange to the hard line and a while I'm at it I rebuilt my vacuum pump with all new gaskets, plus few other items. My lower heater core hose is new and so far everything is bone dry. Of course I only use genuine VW/Audi parts and never run into problems.
I didn't want to risk changing o ring on aftermarket part if it was a oem unit I would have. The vacuum pump they sell seal kits I did a video on it easy
First try changing the o-ring on the lower (leaking) heater core hose. I just did this job - New Coolant Flange, Upper Short Hose from flange to the hard line and a while I'm at it I rebuilt my vacuum pump with all new gaskets, plus few other items. My lower heater core hose is new and so far everything is bone dry. Of course I only use genuine VW/Audi parts and never run into problems.
I didn't want to risk changing o ring on aftermarket part if it was a oem unit I would have. The vacuum pump they sell seal kits I did a video on it easy
What is the part number of the seal?
Make more Audi B7 videos on anything.