Audi Q7 Thermostat Issues Causing Temperature Swings

Had a very similar issue with my 2014 Audi Q5 last year and can share some firsthand experience. The symptoms you describe match exactly what I encountered, inconsistent engine temperatures and unpredictable cooling system behavior. After monitoring the temperature fluctuations for a week, I took it to a workshop where they diagnosed a defective map thermostat in the thermostat housing. The thermostat was sticking intermittently, preventing proper coolant flow regulation. This explained both the overheating and the slow warm-up issues. The repair involved replacing the complete thermostat housing assembly. Total cost was 350 Euro including parts and labor. Since the replacement, the cooling system has worked flawlessly with consistent temperature regulation. Before getting it fixed, I noticed the temperature gauge would sometimes spike during highway driving, and the cooling fan would run longer than usual after parking. These were clear warning signs of the failing thermostat. To provide more specific advice for your case, could you share: Current mileage on your Q7, Whether you notice any coolant loss, If the check engine light is on, Whether the cooling fan behavior has changed, If there are any visible leaks around the thermostat housing

Had a very similar issue with my 2014 Audi Q5 last year and can share some firsthand experience. The symptoms you describe match exactly what I encountered, inconsistent engine temperatures and unpredictable cooling system behavior. After monitoring the temperature fluctuations for a week, I took it to a workshop where they diagnosed a defective map thermostat in the thermostat housing. The thermostat was sticking intermittently, preventing proper coolant flow regulation. This explained both the overheating and the slow warm-up issues. The repair involved replacing the complete thermostat housing assembly. Total cost was 350 Euro including parts and labor. Since the replacement, the cooling system has worked flawlessly with consistent temperature regulation. Before getting it fixed, I noticed the temperature gauge would sometimes spike during highway driving, and the cooling fan would run longer than usual after parking. These were clear warning signs of the failing thermostat. To provide more specific advice for your case, could you share: Current mileage on your Q7, Whether you notice any coolant loss, If the check engine light is on, Whether the cooling fan behavior has changed, If there are any visible leaks around the thermostat housing

Last service at 172000 KM. Just to update, took it to a shop who confirmed the diagnosis, definitely a failing thermostat. The temperature sensor readings were all over the place during their tests. The water pump looked fine, but they recommended replacing the thermostat housing assembly since the current one shows signs of wear. The coolant system pressure test showed no leaks, which is good news. They quoted 380 Euro for the complete repair. Will schedule it for next week and update once fixed.

Last service at 172000 KM. Just to update, took it to a shop who confirmed the diagnosis, definitely a failing thermostat. The temperature sensor readings were all over the place during their tests. The water pump looked fine, but they recommended replacing the thermostat housing assembly since the current one shows signs of wear. The coolant system pressure test showed no leaks, which is good news. They quoted 380 Euro for the complete repair. Will schedule it for next week and update once fixed.

Thanks for the update on your Q7. Sounds like it was exactly the same issue I had with my Q5. The erratic temperature sensor readings are indeed a classic sign of a failing thermostat, and its good they checked the entire coolant system for pressure integrity. The quoted 380 Euro is reasonable and close to what I paid (350 Euro). Just make sure they flush the entire cooling system during the repair, this helped prevent any potential issues after my thermostat housing replacement. Since the repair on my Q5, the engine now maintains perfect operating temperature and warms up normally. The temperature gauge stays steady where it should, and the cooling system works exactly as designed. No more unpredictable temperature swings or extended warm-up times. Keep monitoring the coolant level for the first few weeks after the repair. While rare, sometimes air pockets can form in the coolant system during the thermostat housing replacement, but they typically resolve themselves after a few heat cycles. Let us know how it goes after the repair.

Thanks for the update on your Q7. Sounds like it was exactly the same issue I had with my Q5. The erratic temperature sensor readings are indeed a classic sign of a failing thermostat, and its good they checked the entire coolant system for pressure integrity. The quoted 380 Euro is reasonable and close to what I paid (350 Euro). Just make sure they flush the entire cooling system during the repair, this helped prevent any potential issues after my thermostat housing replacement. Since the repair on my Q5, the engine now maintains perfect operating temperature and warms up normally. The temperature gauge stays steady where it should, and the cooling system works exactly as designed. No more unpredictable temperature swings or extended warm-up times. Keep monitoring the coolant level for the first few weeks after the repair. While rare, sometimes air pockets can form in the coolant system during the thermostat housing replacement, but they typically resolve themselves after a few heat cycles. Let us know how it goes after the repair.

Thanks everyone for the helpful input. Quick update after getting the repair done, absolutely spot on regarding the thermostat diagnosis. The shop replaced the thermostat housing assembly and did a complete coolant system flush as suggested. Total came to exactly 380 Euro as quoted. After a week of driving, the temperature regulation is now perfect. The engine warms up normally and maintains steady temperature, even during extended highway drives. The cooling fan is operating normally again, and the temperature sensor readings are completely stable. No more wild temperature swings or extended warm-up periods. Very glad I got this fixed before any major cooling system failure occurred. Will keep monitoring the coolant level as advised, but so far everything is working exactly as it should.

Thanks everyone for the helpful input. Quick update after getting the repair done, absolutely spot on regarding the thermostat diagnosis. The shop replaced the thermostat housing assembly and did a complete coolant system flush as suggested. Total came to exactly 380 Euro as quoted. After a week of driving, the temperature regulation is now perfect. The engine warms up normally and maintains steady temperature, even during extended highway drives. The cooling fan is operating normally again, and the temperature sensor readings are completely stable. No more wild temperature swings or extended warm-up periods. Very glad I got this fixed before any major cooling system failure occurred. Will keep monitoring the coolant level as advised, but so far everything is working exactly as it should.