VetteRN

I've seen a few of you say that you installed shut of valves for your heaters to help with the heat prob. What does this consist of, where did you install? I have noticed that I have a steady flow of hot air coming through, did this seem to make your a/c work better? Thanks

Disco_Mike

the heater shut off valve is a vacuum actuator. you connect it onto the feeder hose to the heater core. when vacuum is applied, it shuts of the hot water to the heater core. on my 79 the vacuum hose from the controler is a yellowish/white plastic vaccuum tube. on the 79 the valve is attacted to the fender skirt. i dont have pics. im reinstalling mine here shortly. hopefully someone will post pics to aid us in this. currently, i have the heater core by-passed. took a short piece of heater hose and connected the inlet directly to the outlet.

Bobchad

See if this helps.
http://home.attbi.com/~jchadwick/ventilation.htm

Bob

joe73vette

I put a hardware store ball valve in one of the hoses. Easy on and off for the seasons.

Bummer is I turned it on the other day and this morning got a heavy mist of coolant out the heater outlets. AAARRRRGGGGHHHH!!!

Joe

Ingar, Norway

I also have an article on the HVAC (1980) system at my page, but this went through large changes over the years.

I was quite surprised to see that the heating is not controlled by a valve, but instead, a door (operated by the cold/hot handle) distributes the air either through the heater core or bypassing it. This door was partly frozen in my car.

The waterpump has an internal bypass-passage so it's no problem to block of the heater core.

If you install a ball-valve I recommend to mount it on the suction side (water pump connection) since the polymer inside these valves tend to disintegrate in high temperatures.

redwingvette

My car did not come with one so I went to Autozone and bought a manual controled valve. I believe it was listed for a 77 Impala. It is setup for a cable to activate it. I just left it unconnected a placed it in the hose attached to the intake manafold. If I need to use it I lift the hood and turn it on. Valve cost about $13.00 and is for 5/8" hose.

Paul L

This may not be terribly relevant for a 1974, but this is the vacuum-actuated valve in my 1979. It does work very well.

PROSOUTH

I found a cute little water valve at AutoZone for my El Camino the other day and it is very compact. I mean very compact. I haven't got a picture of it but it is an inline valve that is operated with a little tee on the top. It is marked Factory Air # 84706 Shut-Off Valve.

I think it was about $7.00. JIM

Ghostrider

I don't understand why you even bother with the vacuum operated or even ball valves in Florida. I drive car in summer only and installed 3/4" and 5/8"brass plumming plugs in water pump and engine of my ZZ-4 and removed both hoses and 3-way vacuum valve but left the heating core (drained) with a flush cut black painted cork. Neatest set up you have ever seen and no "heating problems" any more.

VetteRN

So From what I am seeing, all I need to do is splice the hose coming out of the intake manifold and place a manual valve there. By doing this there is no effect to my waterpump flow - except that to the heater. Is that the just of it???? Thats too easy. Thanks all

john's '81 mouse

Quote: "So From what I am seeing, all I need to do is splice the hose coming out of the intake manifold and place a manual valve there. By doing this there is no effect to my waterpump flow - except that to the heater. Is that the just of it???? Thats too easy. Thanks all"

Yep, that's it, in a nut shell!!!!!!!!!!