I am new to forum. Need Major Help. I have a 2005 A4 Cabriolet 1.8 Turbo that recently purchased.

Car is overheating mainly within 5 minutes of running at average neighborhood speed. The problem started with the return pipe which was leaking from an epoxied bleeder hole. Car was not overheating before repair. Replaced pipe and connected all hoses.

After repair it started to overheat at first in 10-15 minutes range and now constantly overheating within a few blocks driving. It doesn't overheat in up to 30 minutes of idle. The top of the motor hoses get real hot. Lower radiator hose is cool and heater core hoses cool. The heater doesn't heat.

Removed thermostat to make sure it was working and it opens ok. I flushed upper hose going to radiator with garden hose and water came out of hard pipe that connects hose with good flow and clean water.

Mechanic and I have given this a lot of thought and research but appear to be overthinking it and need someone with more experience to give me some ideas of what's causing overheating.

 

Just to be sure, you did fully bleed the air out of the system, including the heater core, right?

 

I don't think mechanic did. Can you explain how to do it? I boiled it down, no pun intended, to air in system or bad water pump. What are your thoughts?