THanks both. There is definitely coolant in the expansion tank, but I don't think it is holding any pressure. Not sure what pressure it is rated at, but the handbook suggests it should be removed carefully when hot as steam may escape. Mine does not seem to be holding any pressure at all - it does not seem right that with the car at full operating temperature, and running at idle, I should be able to remove the pressure relief cap with no apparent loss of pressure. That indicates the cooling system is running at atmospheric pressure which is clearly wrong.
Pretty sure the head gasket has not failed - no reason why it should have done so, the car was fine previously and the only thing that has changed is the radiator replacement, so I am currently thinking the expansion tank and/or cap might be dud. It would be very useful if any 4/4 Zetec owners here can tell me:
- is the expansion cap on your car on tight?
- if you try to remove it when hot, does it appear pressurised?
thanks
Mark
