VW Polo AC Failure After Mechanic Visit Raises Concerns

Had a similar situation with a 2013 VW Golf 1.4 TSI. The temperature sensor malfunction warning came after routine maintenance too. Initial diagnosis pointed to a faulty G62 coolant temperature sensor, but the actual issue was more complex. The heat exchanger had developed a small coolant leak that was affecting the AC control unit. The seeping coolant had corroded some of the electrical connections to the temperature sensors, causing false readings and system shutdowns. This is a known issue in some VW models from that generation. The vehicle maintenance revealed multiple problems: Corroded wiring harness near the temperature sensors, Failed sensor calibration attempts due to the coolant leak, Heat exchanger replacement was necessary, AC control unit needed thorough cleaning and connection repair This was not a simple sensor replacement job. The entire cooling system needed inspection and repair to prevent future sensor malfunctions. The symptoms match your situation, AC shutdown, error codes, and temperature warnings. Would strongly recommend having the entire cooling system checked, particularly the heat exchanger area and sensor wiring. These issues typically worsen if left unaddressed.

Thanks for sharing that detailed experience. I had that exact same frustrating temperature gauge problem on my 2012 Polo last summer. Really sounds identical to what you dealt with, the HVAC system completely shut down and sensor errors kept popping up. Did you remember roughly what the total repair cost was for fixing everything? Just curious since my repair bill ended up being quite steep with all the cooling system work required. Also wondering if youve had any temperature-related issues pop up since getting it fixed?

Thanks for asking about the costs. Just had everything sorted last month and the total came to 980€ for the comprehensive fix. The cooling system is now working perfectly with no temperature sensor warnings since the repair. The mechanic found the heat exchanger was indeed causing the problems, much like in your case. They had to replace the faulty temperature sensor and repair the air conditioning control unit which had been damaged by the leaking coolant. Engine cooling is now spot on and the AC runs like new. No more error codes or system shutdowns. Getting the complete repair done rather than just replacing sensors was definitely worth it, even though the cost was significant. These VW cooling system issues really need a thorough fix to prevent them from recurring. The vehicle maintenance history now shows all the cooling components are up to current specs, which should help with resale value too. If your repair costs were similar, it seems that was the going rate for this type of comprehensive cooling system work.

Just got back from the mechanic after dealing with my Polo's temperature issues. My total bill came to 1150€, definitely not cheap but seemed fair given all the work needed. The main culprit was exactly what you described, a failing heat exchanger that had caused coolant leaks and sensor problems. They found corroded wiring near the HVAC system and had to replace several components including the temperature sensors. The cooling system needed a complete flush and the mechanic showed me the damaged parts which helped explain the high cost. Really glad I didnt just try replacing the sensor alone. Been driving it for about a week now and the temperature gauge is working perfectly. No more error codes and the AC is blowing cold again. Feels like a different car honestly. Thanks for steering me toward getting a thorough check rather than a quick fix, probably saved me from bigger problems down the road.