serrobert

Update for whoever finds this thread in future. Apparently my expansion tank is a different revision and has no physical silica bag inside. So no burst silica bag. Also checked with VCDS for errors but aircon unit had no faults. I ordered an original Valeo heater matrix from Germany for less than 100€, disassembled the entire central tunnel and replaced it. No leaks around the AC site, but the old heater matrix was almost 100% blocked. After cleaning it I tried to blow inside but only very little air was coming out. Compared to the new it was day and night. Reassembled everything, refilled the lost coolant, reset all the errors. Aircon works again, even hotter than before. After another small trip of 1000 km coolant level seems to be stable. Will keep an eye on it in the next weeks.

Thanks for the answer, no wet carpets around driver nor passenger side. Still have to inspect the expansion tank, wife drove the car (no signs of overheating luckily) and it was still pretty hot. That's the situation under the expansion tank. My idea is that the heater core is clogged / partially clogged resulting in an increased pressure in the cooling system.

Good morning everyone, I'm looking for a possible solution to a recent problem I'm having with my A3. It's a 2014 8V 2.0 TDI currently sitting at 163.000 km / 101.000 miles. Recently I noticed the coolant level not being consistent and no heat when using a/c. I topped up the coolant to the "max" line (car cold) before a long trip I had to take (500 km / 310 miles). The next day (car cold again) the coolant was again under the "min" line. Car was running fine the whole trip, without overheating with oil temperature in the 98-103 °C range (208-217 F). No heat in cabin the whole time. I recently serviced the car and replaced diesel, air and oil filters, along with a full change of oil. Old oil was clean black and not contaminated - I'd exclude a failing head gasket. Aircon controls works fine and putting it on max blasts cold air at full force. Yesterday I suddendly had hot air again. Stopped for some errands, coming back no hot air again. Once home I checked the engine bay for the coolant level and saw a lot of coolant in the engine bay, directly under the container. I'll inspect it for cracking or leakage, but could it be linked to the missing heating or it's probably the heater core matrix too?