XTS Radiator Fan Failure Causing Engine Overheating

Had a similar issue with my 2016 Cadillac CT6. The cooling system started acting up, showing the same symptoms you described. The engine cooling was compromised and the radiator fan stopped working properly. After checking the car radiator thoroughly, my mechanic discovered a faulty speed sensor that was preventing the fan from engaging at the right time. The repair took about 3 hours and cost me 250€ including parts and labor. Since the fix, the fan noise is back to normal and the engine temperature stays steady. Based on your description, it sounds very similar, but to provide better guidance, could you share: Current mileage on your XTS, When was the last cooling system maintenance done, Are you noticing any coolant leaks, Does the fan ever turn on, even at high temperatures, Any unusual noises from the engine bay These troubleshooting details would help narrow down if youre facing the same issue I had with the speed sensor or if its something else in the cooling system. Best to get it checked soon, as overheating can lead to more serious engine damage.

Last service was at 113945KM when I had the oil changed and basic inspection done. The mechanic didnt mention any cooling system issues at that time. The fan motor is completely silent, even after the car has been running for 30 minutes. There are no visible coolant leaks under the car or around the radiator. The temperature control issues seem worse in heavy traffic. I did notice a slight clicking sound coming from the thermal switch area when the engine is hot. I am thinking about checking the speed sensor as you suggested, since the symptoms match closely with what you experienced. Did you notice any warning signs before the complete fan failure in your case? My main concern is preventing potential engine damage while diagnosing the exact cause.

Thanks for providing those details. Having gone through this with my CT6, I definitely understand your concern about potential engine damage. Looking back, before my speed sensor completely failed, I did notice the fan blade would occasionally work intermittently, especially during idle. The clicking sound you mentioned from the thermal switch area is very similar to what I experienced, it was one of the early warning signs I initially overlooked. The absence of coolant leaks is actually good news, as it narrows down the potential issues. In my case, the car radiator itself was in perfect condition, which made the diagnosis point more clearly to the electrical components of the cooling system. Since your symptoms match my experience so closely, I suggest having the speed sensor checked first. The repair is relatively straightforward and much less expensive than dealing with major engine damage from prolonged overheating. The fix on my CT6 has lasted well over 45000km now, with no recurring issues. Just keep in mind that while driving to the shop, try to avoid heavy traffic situations and keep an eye on that temperature gauge. If it starts climbing too high, pulling over and letting the engine cool down is the safest approach. Worth noting that the total diagnostic and repair time should be around 3-4 hours if its the same issue, and parts costs have remained fairly stable at around 250€.

Thank you for the helpful information and sharing your experience. Those warning signs you mentioned definitely match what Im seeing with my XTS. That clicking sound from the thermal switch has me particularly concerned now that you mentioned it was an early warning sign in your case. Since my car is showing identical symptoms to what you experienced, I will schedule an appointment to have the speed sensor checked first. The repair cost and time frame you mentioned seems reasonable, especially compared to potential engine damage costs. Until I can get it into the shop, I will be extra careful with monitoring the temperature gauge and avoiding situations where the cooling system might be stressed. Good to know the fix has been reliable for you over 45000km, gives me confidence this could be a long-term solution rather than just a temporary fix. I really appreciate you taking the time to share such detailed information about your experience with the radiator fan issues. This will help me communicate better with my mechanic about what needs to be checked first.