Hi Guys,

3 week's ago I noticed that my best in the world car has problem with overheating. The symptoms were strange as car heated up to ¾ of temperature scale and after couple seconds came back to normal. So I went to mechanic and he told me that there is problem with viscotic fan clutch and this should be replaced as a first. Just in case I have also replaced water pump and v-ribbed belts. I collected car last Sunday and for about 2 hours everything was ok then after car started heat up again. I rang mechanic and explained what happened then he advice me to open valve on rubber pipe as maybe some air in the cooling system. I did it and symptoms gone. Then again today was driving for about 2 hours and problem came back. What's wrong with this car. It doesn't overheat straight away but after couple hours. Mechanic said that thermostat is working properly and he tested car before I collected but he never drove this car. Just tested in garage. Any idea?

Thanks.
[hr]
Forgot to mention. My car is e46 320i m54 engine.