Folks,
My 77 has a valve that stops the flow of water to the heater core to diminish the heat in the car. Will the core be damaged if the valve is never opened? Also, if I do ever want to open the valve is it as simple as turning the valve or should anything else be done.
Thanks,
Chris

Yo, Chris,
I'm not a professional mechanic, but looking at other postings in this section of the forum, it appears that the valve simply stops the hot water from flowing. Your heater core should still have water in it as the return hose should still be attached to the water pump. If it isn't, you may have a bad heater core and the valve is simply a quick fix to stop the leak. If you turn the valve on and you don't get heat or very little of it, you may need to backflush the core. Also, you may want to see if the stock valve is working by moving the heat and temp. selectors and seeing if the vacuume can moves the contol valve one way or the other.

I plan to put in one of these valves next spring. My 79 is a real foot cooker when it gets hot.

Good Luck,

SHRKATTK said: Folks, My 77 has a valve that stops the flow of water to the heater core to diminish the heat in the car. Will the core be damaged if the valve is never opened? Also, if I do ever want to open the valve is it as simple as turning the valve or should anything else be done. Thanks, Chris

Not sure how helpful this is, but check out the thread called "Heater Hose Valve"