Cabin Temp Tip

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63valiant

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[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]Thought I'd share this with you guys. As some of you may know, I've been R&Ring my heater box, replacing the core, and cleaning my cowl vents in my '63. When I put it all together I decided to try a trick from the Days of Olde and put a manual shut off switch in the coolant line that supplies the heater core. I used 4 Seasons Part # 84706 around $15

With the coolant turned off I drove into town with my infrared thermometer. I checked the heater box temp with the gun, it was just over 94 degrees. (Ambient temp was around 94). Turned the valve on and drove home. Temped the box again and it was 135 degrees!!! You can see shutting that coolant of seriously reduced the heat entering the interior of the car. That alone should help in the hot summers. I plan on adding AC to this car so this can only help that work better.
Just a FWIW.


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I have been trying to get around to that myself, although I did insulate all the exposed tubes when I replaced the core to help a little.

It helps if the air doors seal well but it'd still be nice to shut the coolant/hottant to it off all the way.
I was hoping to avoid a hot metal valve handle, so I was thinking to use a ball valve with the insulated handle.
Yours is compact though, and thats something to consider also.

It's on the list. :)
 
Great idea! Never could figure out why Ma Mopar didn't put a valve in instead of just closing a door. I guess that's why they went overkill on the vents. LOL
 
Great idea! Never could figure out why Ma Mopar didn't put a valve in instead of just closing a door. I guess that's why they went overkill on the vents. LOL

Some did have a valve and some didn't and thats the part that I was having a hard time trying to figure out. :)
 
Cool tip.


It doesn't matter what temperature a room is, it's always at room temperature....
 
Factory a/c builds have a vacuum operated water valve. The high end aftermarket a/c systems include one also.
Some vehicles have a cable operated valve. Granted you would need to mount the valve and cable pull somewhere.
 
Granted you would need to mount the valve and cable pull somewhere.

I thought about that too, because sometimes it's nice to have a little heat early in the morning, but then you don't need/want it all day or for another month.
The last two summers I told myself I was going to put a valve in there but still havn't done it.
I guess that says how important it is. :)
 
Funny someone brings this up. My wife and I noticed our classic air isnt doing the job as we feel heat coming from under the dash. Is the flapper door or deteriorated foam on the door whats causing this? I thought about disconnecting the heater core and putting a loop under the hood for hot weather.
 
Funny someone brings this up. My wife and I noticed our classic air isnt doing the job as we feel heat coming from under the dash. Is the flapper door or deteriorated foam on the door whats causing this? I thought about disconnecting the heater core and putting a loop under the hood for hot weather.

If there isn't a shut off valve the heater core is close to engine temp all the time, and yes a leaking door seal compounds the problem.
But even if the foam seals are good (mine are all new) that heater box still gets pretty hot.
What works really well for those doors is that grey foam door and window weatherstrip that you can get at any hardware store.
The stuff about 3/8 wide and 1/8-3/16 thick with the sticky backing works fantastic, but you have to clean the attaching surface well before you put in on or it won't stick well.
If you decide to do it watch out for positioning of the seal because the seal surface isn't always the same shape as the door and it's easy to miss a corner here and there.
 
Yep, sealing the vent and blend doors is only going to do so much. The box will still get hot with the coolant flowing through it so it'll pass plenty of conductive heat.

I can vouch for that metal knob getting real hot! Confirmed it when I did my test.:sunny:

Originally I wanted to use a ball valve, but wasn't having any luck finding one that would accept the 5/8 fittings. Seems 1/2 and 3/4 are the common sizes. So I did some looking around and came up with the 4 Seasons part. Looked like a cost effective and simple method to do what I wanted.

If you want to get more involved with it the cable control is one way. Another would be to use a vacuum shut off like what's used in most "modern" vehicles. You'd just have to come up with a way either mechanically or electrically to turn the vacuum off and on.
 
My 64 D100 has a manual valve under the hood. It shows it in the FSM. It also has a recirculating heater (no fresh air through heater). It has to be shut off in the summer or it will cook ya. 72 Dart has the vacuum operated valve, AC car.
 
Thanks Trailbeast! Think Im gonna loop the heater hose. Has anyone ever tried connecting an unused heater core under hood just on the other side of the fire wall? A little extra radiator capacity in dealing with the heat and no heat in the cabin? A win-win?
 
Yep, sealing the vent and blend doors is only going to do so much. The box will still get hot with the coolant flowing through it so it'll pass plenty of conductive heat.

I can vouch for that metal knob getting real hot! Confirmed it when I did my test.:sunny:

Originally I wanted to use a ball valve, but wasn't having any luck finding one that would accept the 5/8 fittings. Seems 1/2 and 3/4 are the common sizes. So I did some looking around and came up with the 4 Seasons part. Looked like a cost effective and simple method to do what I wanted.

If you want to get more involved with it the cable control is one way. Another would be to use a vacuum shut off like what's used in most "modern" vehicles. You'd just have to come up with a way either mechanically or electrically to turn the vacuum off and on.

Guess you'll just have to hang a potholder on the firewall for that. :D
I was wondering about the ball valve size thing, but like I said I have not got into doing it yet so I hadn't found that out.



Thanks Trailbeast! Think Im gonna loop the heater hose. Has anyone ever tried connecting an unused heater core under hood just on the other side of the fire wall? A little extra radiator capacity in dealing with the heat and no heat in the cabin? A win-win?

A heater core won't help much at all unless it's in direct airflow, and the not much because there is just to little surface area to make much differenceThey only hold about quart of coolant also.

When you loop that be sure and cap your core off so mud wasps and bugs don't build homes in it and end up plugging it up.
 
Thanks Trailbeast! Think Im gonna loop the heater hose. Has anyone ever tried connecting an unused heater core under hood just on the other side of the fire wall? A little extra radiator capacity in dealing with the heat and no heat in the cabin? A win-win?

Why would you do that though, some sort of religious reasons not to use a valve? For $15 I would think it would be worth it to have on/off capability when wanted, not stress the heater core by constantly pushing and pulling hoses on and off, and losing coolant which is pricey in of itself.
 
Do a 'Part Number Search' on www.rockauto.com and you'll see that Four Seasons PN 84706 can be purchased for $8.32.
It also shows the application to be for 1969-70 Dodge A100, 1969-71 Dodge D100-D300 and W100-W300 pickups.
Looks like a "winner" in my book. Thanks, 63valiant!
 
Why would I? Good question. I just thought with a shut off valve the engine would run slightly hotter because the coolant really isnt moving through the hoses like it would if it was looped. Gonna run out and get a valve at Auto Zone. And 9 bucks is a deal. Thanks for the timely post 63valiant. Its gotten very hot in Jersey the past 2 weeks. Im sure this thread has gotten alot of views! Update-Napa up the street has one. No more cabin heat after today.. Nothing religious. Thanks again for bringing the topic up.
 
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