SQ8 Engine Cooling Symptoms Point to Radiator Issues

Having dealt with similar engine cooling issues on my 2020 Q8 55 TFSI, I can share my experience with this. I have some experience working on Audi vehicles and their cooling systems. The symptoms you describe match what I encountered. Initially thought it was a radiator grille blockage, but after inspection, it turned out to be a blown fuse controlling the cooling system electronics. The engine overheating warnings were inconsistent because the temperature sensors weren't getting proper power. Had it checked at a workshop where they diagnosed and replaced the faulty fuse, costing 52 Euro for the complete service. Since then, the temperature readings have been stable and the engine cooling system works perfectly. Before heading to a workshop, could you check: 1. Are you getting any specific error codes? 2. Does the cooling fan activate when the engine is warm? 3. Have you noticed any coolant leaks? 4. When exactly did these symptoms start? Also, what trim level is your SQ8 and have you had any recent work done on the cooling system? This information would help identify if we are dealing with the same issue. Remember to check your coolant level and look for any visible obstructions in the radiator grille before taking it in for service.

Thanks for your detailed analysis. Last service was at 10000 KM and current mileage is 13288 KM. I checked the OBD codes and got P0116 and P0118, both related to engine coolant temperature sensor circuit. The cooling fan does activate, no visible leaks, and I have checked the coolant level which is normal. The thermal management issues started about 2 weeks ago, first with inconsistent temperature gauge readings, then the check engine light. Based on what you mentioned about the fuse, I will check the fuse box. The car overheating symptoms match what you described, erratic temperature readings and extended warm-up times. The engine cooling system otherwise seems to function, but those sensor readings are concerning.

Thanks for providing those details. The OBD codes P0116 and P0118 actually point to a different issue than what I experienced, though the symptoms are similar. While my engine cooling problems were resolved with a fuse replacement, your codes specifically indicate a coolant temperature sensor malfunction. In these cases, engine overheating warnings can be misleading since the car relies on accurate sensor data. The extended warm-up times and inconsistent readings on your SQ8 match the typical behavior of a failing temperature sensor rather than a radiator blockage or fuse issue. The workshop repair for a temperature sensor replacement typically runs around 180 Euro including parts and labor. Since your vehicle is fairly new with only 13288 KM, this might even be covered under warranty. Quick questions: 1. Have you noticed any changes in fuel consumption? 2. Is the radiator grille clear of debris when you inspect it? 3. Does the temperature fluctuate more during highway driving or city traffic? While checking fuses is a good first step, based on those specific codes and my experience with similar engine cooling issues, I recommend having the temperature sensor checked professionally. This is especially important to prevent potential engine overheating damage from incorrect temperature management.

Thanks for the thorough insights. After inspecting the fuses, all look fine. You make a good point about the codes pointing to the temperature sensor rather than other automotive cooling components. Regarding your questions: 1. Fuel consumption increased about 12% according to the onboard computer 2. The radiator grille is completely clean, I checked thoroughly for any blockages 3. Temperature readings fluctuate more during city driving, especially in stop-and-go traffic I agree that the sensible next step is getting the temperature sensor checked professionally. Since the car is still under warranty and these engine cooling issues seem linked to faulty sensors rather than mechanical problems, I will contact the dealer tomorrow to schedule a diagnostic appointment. Better to address this now before any potential engine overheating causes more serious damage. Thanks for helping narrow down the likely cause. The OBD codes combined with the symptoms definitely suggest a sensor issue rather than my initial suspicion about a blocked cooling system.