I have a 1980 MGB which has been showing overheating without a clear cause. I had lost fluid and could not identify where from. Yesterday was very cool in Northeast and I drove with the interior heater on for five minutes and stopped for a few minutes . When I returned to the car I realized I had dropped most of the coolant and when I looked under the hood I saw the fluid gushing out of the control valve for the interior heat. what is broken ?
interior heater was put on for a couple minutes and shortly after the car was
spewing coolant out of the control mechanism near the head on the left side of
the block. photo below. What causes this ?
