Hi all just got home both pipes to my radiator are hot pressurised but the radiator is freezing and expansion tank bubbling like mad throwing coolant out of over flow. So thought water pump must be working with pipes pressurising. So went to see if thermostat shot. In doing so the spanner slipped and it what I think is a sensor next to housing and smashed it off. Any input on any of these would be much appreciated thanks Steve.