Cooling problems on Audi S1

It sounds like the thermostat might be sticking or not functioning properly, even if it's electronic. Try checking the thermostat housing and connections for any signs of corrosion or damage. Also, ensure that the coolant level is correct and that there are no air pockets in the system, as these can affect the thermostat's operation. If the issue persists, it might be worth having the thermostat tested or replaced. Keep us updated on your progress, and let us know if you have any further questions.

The fluid level is always correct... there doesn't seem to be any corrosion on the wiring. Replacing the thermostat is expensive in Italy; before replacing it, I'd like to be sure... Another thing is that the pipe above the radiator is boiling hot and the one below is cold. The car never overheats; the temperature is always correct, even with very hot outside temperatures.

(Translated from Italian)

Consider checking the radiator for any blockages or restrictions that might be preventing proper coolant flow. A clogged radiator can cause the symptoms you're describing, with uneven temperatures across the radiator. You can try flushing the radiator to see if it improves the situation. If the problem persists, it might be necessary to have a professional inspect the radiator and cooling system more thoroughly. Let us know how it goes or if you have more questions.

I had also thought it seems like the radiator is closed...but then I said to Audi, it has 85,000 km, the water is always clean, it doesn't seem to have traces of scale or anything else...anyway, I'll do a test to rule it out, thanks

(Translated from Italian)

I bought the used car a short time ago and hadn't noticed this defect because I only drove it a few kilometers during the test drive and it seemed to be fine.

(Translated from Italian)

It's possible that the previous owner didn't notice or disclose this issue. Since you've ruled out some common causes, consider checking the water pump for proper operation. A failing water pump might not circulate coolant effectively, leading to the symptoms you're experiencing. If you're unsure, it might be best to have a professional inspect the water pump. Keep us updated on your findings, and feel free to ask if you have more questions.

Check if the radiator cap is functioning properly. A faulty cap can cause pressure issues in the cooling system, affecting coolant flow and causing the fans to behave erratically. If the cap seems worn or damaged, consider replacing it. Let us know if this helps or if you have further questions.

I'm wondering if the pump was broken, the car would overheat, or if the thermostat was broken, it would overheat, but this isn't happening... the cap on the expansion tank doesn't seem damaged or anything... the car seems brand new in everything, but if I open the cap while the car is running and hot, the water tends to come out with great pressure... I don't know if that's normal.

(Translated from Italian)

It's normal for the coolant to be under pressure when the engine is hot, so be cautious when opening the cap. Since the car isn't overheating, it might be worth checking the coolant temperature sensor. A faulty sensor can send incorrect signals to the fans, causing them to run unnecessarily. If you have access to diagnostic tools, you can check the sensor readings to ensure they're accurate. Let us know how it goes or if you have more questions.

Maybe I understood, I found the broken silicate bag in the radiator reservoir. Most of the silicates weren't there, and very few remained in the bag...could they have plugged my radiator???

(Translated from Italian)