Believe me, this doesn't make sense to me either. I tested the brand new heater valve and it does not leak. I also removed the linkage from the vacuum pot and wired it shut.
Looking at Tony's site, it could largely be due to the center flap. Both my center flap and heater actuators are leaking.
It takes a while for parts to arrive up here, so I will have to wait until these arrive to do further testing. Thanks for all your help.

 

Tim: Right, it makes no sense. The heater valve physically blocks flow of hot water from the block unless defective OR somebody somehow misrouted the hoses to the heater core. You could clamp the hoses to and from the core and see if this gives you another clue.

 

Hi Tim,
When you start off in the morning with a cold engine, do you get cold air for a few minutes? Is your a/c condensor real hot to the touch on the upper passinger side? I'm trying to see if you are getting any refrigeration functioin in addition to possible heat contamination. I sounds like you had a leak early on in the post.

 

I physically checked the heater valve by removing it, and blowing through it; both the old one and new unit. they both sealed well in one direction, but would allow some flow in the reverse direction. I have removed the actuator arm, and wired the valve shut so that (presumably) there is no water entering the heater core. The air temp on startup is nice and cool, but does warm up after the engine reaches temp. part of the problem is the center vent, which needs an actuator replacement. I am waiting for two actuators and an inside air temp sensor to arrive, and then test it again. It is very odd that the air temp would increase, considering that there should be no hot water entering the heater core.

 

If you're absolutly positive that the water valve is sealed (glue the old one closed) completly the only other heat is from the engine bay or the outside ambient air. As previously mentioned check the recirc flap; is it set for inside or outside air?

Is there any possible leak from the engine bay into the cab of the car? How hot is the return water pipe from the heater core?

 

Hi Tim,
While it is easy to blame heater valve for these symptoms, there are a number of a/c conditions which act the same way. Do you know what your high and low side refrigerant pressures are? You may be low on freon and have just enough to keep the compressor running but not have enough cooling capacity to overcome the heat of the engine. Also if you have leaking actuators, you may not have enough vacuum to your actuators to keep them in the "cool" position. Wiring the heater valve closed should help that though. When I got my car, my 4-way vacuum fitting was disconnected. I put it back together and voila: cold. I'm sure you've gone way past that in your investigations but if you have open vacuum lines you may have the same effect. You would be better off plugging any vacuum lines that are leaking at the distribution block next to the gas pedal.
Good luck,

 

I just had a shut off valve installed on the hose that feeds the heater... cheap fix, in winter I can turn the heat back on... amazing how cold the a/c is now.... no need to replace parts in hard to get to places!

Rick

 

There is a micro switch in the center console.
What is it for?