Overheating Problem

[Bludger]

see, that's what I thought too. I fill up the rad through the metal cap, and only leave a little bit of water sitting in the bottom of the plastic expansion tank. if that tank was full up then all it will do is overflow when the water heats up, leaving you with not enough water in there the next time! could this be the source of your problems?

Could be. I've fitted a new rad cap, and the new thermostat will hopefully go in this weekend, so I'll keep you posted.

Thanks for all the advice