How do I fix the overheating issue in my Audi 80?

I have a 1995 Audi 80 and it seems to be overheating frequently. The temperature gauge rises quickly and then goes back down after a few minutes. I've replaced the thermostat and checked the cooling fans, but the issue still persists. Any suggestions?

First, check the radiator for any blockages or leaks. You can also try flushing the radiator with a mixture of water and radiator cleaner. If that doesn't work, it's possible that the head gasket is blown. You can check for this by inspecting the oil for any signs of coolant.

Another potential issue could be a faulty water pump. If the pump is not circulating coolant properly, it could lead to overheating. I suggest having it checked and replaced if necessary. It's also a good idea to inspect all hoses and connections for any leaks or faults.

In some cases, an overheating issue can be caused by a faulty thermostat. Make sure the new thermostat you installed is functioning properly and is the correct one for your Audi 80 model. If the issue persists, it may be a good idea to take it to a mechanic for a more thorough diagnosis.