AudiAllTheWay

If you’re having difficulty determining which part numbers are under the intake then one option is to provide your VIN to the local Audi Dealer Parts Dept and ask for a parts quote. A written quote will have all the updated part numbers for your specific engine.

The PCV Oil Separator is considered a wear item as they don’t last forever. In addition to the rubber diaphragm tearing they can accumulate internal dirt with age. I replace them every 100,000KM as preventative maintenance. Similar to valve cover gaskets, the separator rubber seal material has likely aged out and become brittle which can cause a coolant leak.

Since you recently replaced the thermostat then there is not much else under the intake that can leak coolant. The front to back coolant pipe needs to be removed in order to replace the PCV Oil Separator so you could consider to replace this pipe if it is plastic, and a new o-ring where it attaches to the front coolant cross over pipe.

24V6BDW

Work in progress..




I find a zip tie in Cyl 6 intake:


And of course, valve stem seals are leaking.
Nice..


Update: someone was here before, I see that PCV was glued with black RTV.