i am wondering if anyone can help. i have a 99 GCL and it has just started overheating - this accompanied by the loss of all heat in the cabin.
i assume something is blocked - but i don't know where to start. Cheers,

Start by checking the fluid level in the resovoir and then in the radiator itself. Check the small hose going to the resovoir to the radiator, if leaking there you will loose fluid and it's hard to detect.

Sounds to me either your fluid is low...start by checking overflow and the radiator..

Could be a stuck Thermostat. And even worse a bad Heater Core, but that wouldn't have anything to do with overheating unless its leaking and not making it into the Cabin.

I'd say, low fluid or thermostat. Both cheap fixes.

Thanks for the replies. i managed to get to the bottom of it, the issue seemed to be an air blockage!!
the resovoir was full but when i put the hose in the radiator the air came bubbling out. i also undid a few hoses and the tempreture guage dropped back to normal, and the heat returned!!
Thanks again,