Hello, I replaced the thermostat and heater core on my 2006 Passat 1.6 FSI. It was fine for a few days, the inside of the car got nice and warm. Then one day I came back from a 1-2 hour drive, turned the car off, opened the coolant reservoir cap, the water level rose, I closed it right away. Then the car started running the fan, it's not blowing warm air into the cabin
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It's most likely the thermostat, if you fix the problem and write about it here too, other users could benefit from it
Translated from Turkish·You could post on the forum too, you might get more responses
Translated from Turkish·The most likely reason is air trapped in the system. When the thermostat and heater core are replaced, if the air isn't bled out properly, it shifts on long trips, the fan kicks in but the heater doesn't blow hot air. If one of the heater hoses is hot and the other is cold, that's a clear sign. Also, the coolant level and any small leaks should be checked.
Translated from Turkish·I asked Technica AI, it said this
Translated from Turkish·I suspect it's the thermostat, but what do you think the cause is
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