I have a 2006 Audi A4 1.8. My car has been overheating for a while now but only does it during the warm parts of the year. Mostly at 70 degrees or higher weather. While driving the vehicle I have no problems with the vehicle. The problems start when stuck in traffic or when just idling. The vehicle will be fine when idling then all of a sudden it begins to overheat and does so quickly. It rising from the normal point to the hot point very quickly. The first shop I took it to had no idea what was going on. I took it to another shop and they replaced the cooling flange, thermostat, and temp sensor and told me it was fixed. After paying them over $1000 for this work I was driving my car the next day and it began overheating in traffic again and a/c went from cold to warm as it was overheating. I called the shop and told them the problem was not fixed. I haven't worked much on these cars so I'm not sure where to start but wondering if anyone has any idea what it could be before the shop tries to tell me something else is wrong when it isn't.

Thanks

 

The factory water pump has a plastic impeller that is known to break and/or separate from the shaft. When this happens, the water pump is unable to 'pump' coolant throughout the system and the car will overheat. When is the last time the water pump & timing belt were replaced?

 

Both were replaced in 2015 at about 93,000 miles. Took it back to the shop and it was the fan control module. Thanks for the help