RSQ3 Cooling Crisis: Fan Issues Cause Engine Overheating

I had a similar issue with my 2014 RS3. As someone who does basic maintenance but leaves complex repairs to professionals, I understand your concern about the engine cooling system. The symptoms were nearly identical, inconsistent fan noise and rising engine temperature. After monitoring the car radiator and fan motor behavior for a few days, I took it to a workshop. The diagnostic revealed a faulty speed sensor that was causing incorrect readings, leading to improper thermal switch activation and engine cooling issues. The total repair came to 250 Euro, including parts and labor. Since the fix, the cooling system has worked flawlessly, and the fan kicks in exactly when needed. To better assist with your specific case, could you share: Current mileage, Any recent repairs or maintenance, Whether you notice any coolant leaks, If the problem occurs more during idle or while driving, Whether you hear any unusual sounds from the fan motor area These details would help determine if your issue matches what I experienced or if it might be something different in your engine cooling system.

Thanks for the detailed reply. My Audi RSQ3 has 148201 KM and I had its last service done 3 months ago. A routine check showed no issues with the temperature control system at that time. To answer your questions, no coolant leaks visible and the fan noise inconsistency happens mostly during idle. The fan motor seems particularly erratic after short drives when the engine is warm. No unusual sounds beyond the intermittent fan operation. My temperature gauge starts climbing about 5-10 minutes after startup, regardless of driving conditions. The engine cooling system worked perfectly before this started happening last week. Would you recommend checking the speed sensor first based on your experience?

Thanks for those details, your symptoms match my RSQ3 experience even more closely than I initially thought. The behavior of your temperature control system, especially the timing of the temperature rise and the fan blade inconsistency during idle, strongly suggests a speed sensor issue similar to what I faced. Since your car has 148201 KM, the speed sensor degradation timeline makes sense. The way your fan operates intermittently, particularly after short drives, is exactly how mine behaved before the repair. The fact that the car overheating occurs consistently after 5-10 minutes is another telling sign. Based on the successful resolution of my issue, checking the speed sensor would be a logical first step. The diagnostic process is straightforward and less expensive than replacing major engine cooling components. My mechanic first verified the sensor readings before confirming it as the root cause. However, since accessing the sensor requires some disassembly, its worth having a professional check both the sensor and thermal switch during the same inspection. This approach proved cost-effective in my case and prevented potential repeat visits. Have you noticed if the engine temperature drops when driving at higher speeds, or does it remain elevated regardless?

Appreciate the follow-up information. The symptoms do sound remarkably similar to your experience. I noticed the car radiator works better and the engine temperature drops slightly at highway speeds, but the cooling system still struggles to maintain proper temperature. Based on your feedback, I will have the speed sensor checked first. The timeline and symptoms align perfectly, especially the inconsistent fan noise during idle and the predictable temperature rise after startup. Makes sense to have them inspect the thermal switch while they are checking the sensor. Good to know the repair costs were reasonable in your case at 250 Euro. Will schedule an appointment with my mechanic this week and have them focus on these components first rather than replacing unusual parts of the engine cooling system. Hoping for a straightforward fix like yours.