So about a month ago my friends B6 1.8t overheated on the highway while he was going to work. He brought it to an indy shop and they replaced the radiator and thermostat. The car still overheats. We brought I to my garage and checked the water pump and got pressure when cold out of the hose from the top rad hose at 3k RPM. Also checked to see if the thermostat was opening up by feeling the lower rad hose to see if it got warm which it didn't so we ordered one from audi and installed it. Bled the system and its still overheating. No codes pending no oil in the coolant, no coolant in the oil and no leaks at all. Any suggestions on where to go from here?

 

have u throughly flushed the system and repurged it. SOunds like a air bubble of sort.