On my 67 Cougar there is constant heat coming from the heater. According to the manual it says improper ajustment blend air valve.
Where is this located? Not sure what it is.
The cable going to the blend air door seems to be ajusted correctly.
It depends on wether or not you have factory AC or not.
Royce yes it does have factory air, it is a 390 S code GT
The heater water is shut off by a vacuum controlled valve mounted on the firewall. Often the valve is bad and it needs replacement. Then the issue becomes one of not enough vacuum because the headlight motors are leaking.
Fortunately the valve has been reproduced so you can buy everything now.
I have already replaced the water valve. I still have heat coming through the system evan with the controll nobb in the off position.
I also replaced all of the vacuume hoses, Might have to recheck to see if all are properly routed.
A vacuum gage will tell if you have enough vacuum at the valve. Often the vacuum switch is no good they are also available as a repop. Also the foam if the unit has never been rebuilt becomes dust after 50+ years.
Ok so with the temp all the way on I have no vacume, With the temp off I have 15-16 psi.
So the vacume switch is working.
What do I need to check next?
I would check vacuum at the valve and then apply vacuum to the valve to make sure it is working.
…also make sure you can see the flapper inside the coolant valve open and shut. My original 70 had an operational vacuum motor, but the flapper inside was corroded away. So it never would stop the coolant flow.
The 67 - 68 version does not have a flapper. It has a piston that comes down and blocks the coolant when it is working.
1 Like