MG Car Repair: MGB 1972 Heater, heater control valve, heat vents

Question
I am getting significant heat from the heat vents/floor area and defroster even though the temp and heater dials are turned to off.

Answer
Hi Jim,
The heater control valve totally controls the amount of heat that the heater core can have but even when you turn off the heater control valve it takes a while for the heater core to expel all of it's heat.

First check to see that the control valve (on the right side of the head) is truly turning off the coolant and that the cable or cable housing has not slipped. You can see if the lever on the valve is moving all the way.

Howard