UK Car Repair Questions? Ask a Mechanic for Answers ASAP
Hi I'm Kevin. This is likely your problem there are really only a couple of possibilities either the water pump impeller has fallen off causing your circulation issue this will be im indirectly obvious when they remove the pump on Tuesday or the thermostat is stuck open. These are really the only two possibilities for no heat and poor circulation most likely the water pump as it's overheating and the thermostat would give other symptoms also . Has the head gasket been tested for failure ?
If the water pump is intact it will not be the cause of the problem I would remove thermostat and test at minimum
No worries it's so easy for them to test while system is drained let me know how you get on
The only way to test for head gasket damage is with a coolant system gas tester this is a tool that passes any air in cooling system through a fluid which changes colour if any hydrocarbons are present in cooling system indicating combustion gasses in the cooling system it doesn't always breach the oil system I would have them test the thermostat also before replacing they only have to put boiling water on it and see if it opens if not replace
Ok perfect come back to me let me know what they find