Heat problem when running idle

[GoCoGi]

My R4 GTL seems to overheat sometimes when running idle for more than 15 minutes or so (water in the coolant expansion tank goes way over max), but I never had problems when driving.

Interestingly, I just noticed that the power wire for the cooling fan is damaged, so that the fan never runs. Could this be the problem, or is this unlikely? What other causes could there be?

 

[malcolm]

The fan not running will cause the problem. Fix it! These engines can blow the head gasket when allowed to overheat.

 

[GoCoGi]

I replaced the fan with a working one, I checked it by replacing the temperature switch with a wire. I have now connected the fan to the temperature switch again, but so far the fan did not start. How long do I have to wait until the fan usually starts?

By the way, how do I know whether my head gasket is still in order?

 

[Bobble]

usually 5 to 10 mins is enough but it does need to get really hot before the fans comes on, it might be the switch that's faulty ? also you have to make sure that you have all the air out of the system as this can lead to bubbling in the header tank if all the air is out it should'nt bubble in the
tank if it does then more thn likely it is the head gasket .

 

[GoCoGi]

Do I have to remove the coolant before I can replace the temperature switch?

 

[Bobble]

yes you will lose some coolant but if the engine is cold you can but you will probably have bleed the system or air then.

 

[GoCoGi]

Thank you, everyone. The temperature actually works. The cable connecting the fan to the switch was not properly attached, as it is slightly worn out. But everything seems to work now. The engine seems not to overheat anymore.