Heater Control

[Thundarr]

I've got a stock setup with AC and the temperature control never quite seems to completely shut off the heater valve. Similarly the AC system checks out, but never quite gets cold. It seems like the AC is fighting the heater.

I have already replaced the Heater valve and check to make sure it is getting vacuum to operate. My next step might be to change out the panel control to make sure it is passing on the full vacuum to the valve. I guess I could just put a manual ball-valve uder the hood to shut down the hot antifreeze to the heater core in the warmer months.

[Wrenchbender Ret]

There is a housing under the dash with a flapper in it. It is notorious for the flapper coming loose. That might be the problem or part of it.

[Grumpy old man]

^^

[Thundarr]

Thanks, I'll check the diagram.

[LockDoc]

-
Also may have a mouse nest in it keeping the diverter door from working....

LockDoc

[Thundarr]

Got it fixed.

Let me explain for some other future poor soul, who messed something up while trying to fix something simple.

After changing out all the old air vent lines, I re-positioned the cable for floor/defrost diverter controls with too much bend. I straightened out the path so now the lever on the control slide panel had its full travel. Because it wasn't able get to its intended end, it kept the temperature control from fully extending so it wasn't fully closing the vacuum line to the heater control valve.

In essence, it wouldn't let the valve shut off the flow of hot water through the core. So in a way, it was a control issue.

Many thanks!
Thundar

[snipescastle2]

I've heard that many of those water control valves never close fully, even new ones out of the box....might be a good move to add a small ball valve to shut off the flow all together.
Ben

[Thundarr]

Originally Posted by snipescastle2

I've heard that many of those water control valves never close fully, even new ones out of the box....might be a good move to add a small ball valve to shut off the flow all together.
Ben

You are absolutely correct. I did a wider search and found Pantera and Corvette club forums that recommend this with vacuum operated heater valves. Mine is better now, but I am going to set up the ball valve shutoff for the hot summer months in Texas. I need every bit of cooling I can get out of that stock AC.

I just picked up this same setup at the hardware store.


Some of their members worry about adding more location to leak coolant so they use clamps to simply pinch off the feed hose to the heater core.


Thanks again to all.

[Thundarr]

Just got the shutoff installed and the difference in the AC is absolutely amazing. The air used to be cool and now it is COLD.

I highly recommend this to anyone in a hotter climate.

[89AKurt]

Originally Posted by LockDoc

-
Also may have a mouse nest in it keeping the diverter door from working....

LockDoc

OMG, you too? I just took a clump of floor insulation and kleenex out the other day. LOL

I have a broken lever, and other issues to work on, project #89.

[LockDoc]

Originally Posted by 89AKurt

OMG, you too? I just took a clump of floor insulation and kleenex out the other day. LOL

I have a broken lever, and other issues to work on, project #89.

Yup, Must have been a mouse motel in mine....

LockDoc

[Andy4639]

I've been running a manual shut off in my 71 for 20 some years now for the summer months. It's one of the best idea's for the AC.
Another great idea is closing off the outside cowl vent totally and having the passenger side kick panel manually operated to cool the cab even more. I can get 38-40* temps on 100* days here in SC.