Excessive Pressure in cooling system

[Tonyr79]

Hello

I have an E1a Major and it has started blowing water out of the overflow in the radiator.

There is no sign of oil in the water or water in the oil but it is pressuring the cooling system and the water comes out of the overflow.

The bottom hose gets hot but the top hose stays cold.

I thought it could be head gasket failure but is there anything else I could try before taking the head off?
Thanks for the help

[oehrick]

might be a duff thermostat, unless you have fitted a pressurised rad filler cap instead of a non pressurised one ? if so it may have developed enough coolant pressure to unseal a liner O ring

[Tonyr79]

thanks for that. It sounds like it might be worth fitting a new thermostat then? Would a proble with a thermostat lead to pressure in the coolant?

[oehrick]

If it boils yes as there is only a trickle going through the thermo into the header (IIRC) if your bottom hose is not that hot then probably not, easy to test stick the thermo in a saucepan or glass bowl and heat the water up over the stove if it opens before the water boils you should be OK (even better if you have a thermometer so you can se what temp it opens at)

If that is not the problem and the coolant is not getting oily then compression leak is probably next most likely

[dwol]

The fins in your radiator may be plugged, not allowing the cooling to happen properly. (may need "rodding" if you can find someone, or just replace) Please verify that proper flow through the radiator is occurring.