Car idles high and overheats.

Need some advice. My car seems to idle extremely high, I'm talking like 2000rpm+, and the engine overheats really quickly. If i'm sitting at traffic lights the engine just boils up. I normally have to turn it off to save the problem. Can anyone tell me what the problem is and how do I diagnose it?

Any help and advice would be much appreciated.
Cheers.

These two faults sound like they are fairly unrelated to each other. Okay so the fast idle isn't going to do the engine over heating any good mind.

First of all does your fan cut in at all? Is there plenty of water in your expansion tank?

I've had the overheating problem when I first bought my golf, it would over heat in traffic same as yours, It ended up being the rad temp switch on the bottom left of the rad. An easy way to check if your fan circuit is fine is by bridging the connections on the plug that attatches to the switch. (I did this with a split pin). If your fan spins up then you need a new temp switch, fairly cheap from GSF.

Your fast idle fault will probably a setting on the carb maybe? you might be able to adjust the fast idle screw back or something?

Could be timing related too maybe?

The fan does cut in mate, but I don't think it's very strong. For a while it wasn't working due to to the leads being filthy and just needing a we clean up, but I got that all sorted. I'll do as you've said though and see what happens.

Cheers very much for the help.

As for over heating

Any signs of coolent leaking, normally leaves a white residue, check top and bottom of radiator and check around pipe connections.
Using any coolent besides boiling over, any signs of oil in the coolent and visa versa?

Does the top hose to the radiator get hot?

Could be head gasket!!

Yeah possible head gasket failure maybe. Or water pump problems, if theres water in the expansion tank and your fan is kicking in properly.