Hi guys, been long time out of the audi scene but came across a deal on an s4 that i couldn't miss.. long story short 2005.5 S4 all new pretty much everything. Clutch, rack, motor mounts 60k mile short block. i went through the heads.. timing stuff T-Stat water pump all new gaskets.. i have allot of time into this project.

Anyhow car runs amazing! Coolant temp normal. Good heat in cabin, but when i pull the car into the shop i heard like a “ Snaping” sound from around the throttle body area… it does this for about 30 seconds after the car is turned off.. so i checked it out… seems there is an air pocket stuck in the small coolant lines and this allows the coolant to boil there.. the rad cap is good and the entire system is under pressure.. you can feel the hose expand a bit with every “ Thump” I bought the car with a blown engine and had to figure everything out so far.. just wanted to see maybe someone has BTDT?
TIA!