Prolific2

I just checked with the dealer after they replaced the ECU and they say that after 20 minutes running the vehicle it still overheated. It seems that they've thrown all the parts at it, and I think they've done the proper clearing of the lines. What would y'all guess the next step would be? I'm sure they've been in touch with the Audi engineers. When it overheats the radiator is cool and the fans are going like crazy, so some valve is not allowing the coolant to flow to the radiator. I think the heater still gets flow though. To my memory there is some other valve in addition to the thermostat valve, that they have replaced.

denis1996

Hello
how was the problem solved? what did they find?

pcc125

I would demand a buyback from Audi. Trade Assist no longer cuts it. Worth a try in my opinion, and you can mention lemon law....

twinpeaks

You've been more than patient - that's enough. I know they are trying but it's time to move on from that car IMHO.

A8bil

This just seems like one of those simple issues that once they figure it out, it'll be like, "Doh!"...but until then it's going to be frustrating. On my V8 Quattro, a lot of owners gave up on the car when it would stall unexpectedly, would intermittently re-start and the dealers would spend months doing everything they could trying to isolate the problem, unsuccessfully. Turned out to be a crank position sensor...$100 part. Bummer for OP though.

KK22

So I got a check coolant light yesterday, and today the car is at the dealer. I had a coolant seal replaced a few months ago and the engine has been perfect since then.

However, with this warning there is no coolant loss, level just above max when hot, there is no overheating of the coolant nor of the engine oil. Really no other symptoms except warning message to check coolant level, which is OK.

I was hoping it was a faulty sensor, but they’ve ruled it out. Just some gremlin that does not seem detrimental to the car, but I don’t feel safe running it hard in the summer without getting it resolved. Thank goodness for factory warranty and the CPO thereafter. Will keep this post updated with whatever they find tomorrow. So far pressure test and sensor test has yielded no leaks and no bad sensors.

derfA8L

Check out this recent TSB. Sounds similar to your issue.

KK22

That sounds EXACTLY like it. Will send to service coordinator right away. Thank you!

derfA8L

👍

KK22

SA said it’s not the thermostat sensor since it’s opening and closing fine. They saw some corrosion on the overflow tank and replaced tank, sensor and wires. Didn’t solve it.

Now Audi “hotline” is recommending changing the thermostat ECM, similar to OPs suggestion above I believe, which is backordered for at least a week ☹️. So I’m rocking an A5 prestige in the meantime.