Heater Host Shut-off Valve

L8knight · Jun 24, 2004

I am replacing a heater core tomorrow on my car and while doing some research on performing the work I came across a good idea - adding a shut-off valve to the inlet line (heater hose) for the summer months (to reduce temps in the cabin). I am interested in doing this, but as I looked for a valve on Napa's website I can't find one without a vehicle make/model.

Anyone know of where I can get one that would fit? I believe the heater hose for my 67 Coupe is 5/8". Maybe someone else has installed one before... not sure how popular of an add-on this is.

Thanks in advance!

302 coupe · Jun 24, 2004

they won't need an application, just tell them you need a 5/8 heater hose shut-off. Somebody will know what you're talking about, they're pretty common. Napa normally has some good help that know what they're doing.

thehueypilot · Jun 24, 2004

Try the after market A/C companies like Classic Auto Air which makes the "perfect fit" system. It has a seperate heater shut-off valve that is manually controlled by a manual "push/pull" cable that is attached to your existing heater control. It is installed inline with your heater hose and when you turn the heat off it closes the valve. I'm sure you can buy the parts from them to do this.

MustangPaul · Jun 24, 2004

Where would you and how would you install the valve? I'm for anything that can get the temps lower inside my car. Sheesh, I'm about to cook, even with AC.

--P

Ronstang · Jun 24, 2004

You simply install the valve inline in one of the heater hoses and then connect the lever on the valve to a choke cable installed under the dash for control. You could also just manually switch the valve under the hood if you added something to hold the lever in place.

MustangPaul · Jun 24, 2004

Ronstang said:
You simply install the valve inline in one of the heater hoses and then connect the lever on the valve to a choke cable installed under the dash for control. You could also just manually switch the valve under the hood if you added something to hold the lever in place.

Ronstang--Well, I'll be damned. How cool is that? (No pun intended.)

Either hose will work? No problems with the engine?

I learn something new every time I log in, I tell you.

-P

GaPonyFarm · Jun 24, 2004

I got one with my Classic Auto Air A/C kit, but here's a "how to" link to a pretty cool (get the pun?) little valve. http://www.eurekaboy.com/f250/heaterhose.htm

You probably want to put the valve on the hose going "to" the heater core, otherwise you would keep pushing warm water in, even though it didn't go anywhere.

D.Hearne · Jun 24, 2004

Four Seasons is one vendor that has in line shut off valves. Their parts are stocked by many local parts houses. One word on the valves though-- don't let them stay open or closed for too long, they tend to freeze up. I used twin inline valves on my 67 back in the 80's for the same reason. They also come in handy ( two that is) when your heater core craps antifreeze all over your floorboards. A single in line one won't help you in that situation.

Ronstang · Jun 24, 2004

You will probably want to put the valve in the hose coming from the intake since it is the "feed" hose to the heater core.

65 fastback · Jun 24, 2004

Nice, I'm getting two.

Thanks,
Tim

Ronstang · Jun 24, 2004

You don't need two valves unless you have two cars.....hehehe.

MustangPaul · Jun 24, 2004

Quick question about the twin valves--any trouble trapping the same coolant in your heater core for extended periods?

Do you need to open them and let them circulate every now and then?

Ronstang · Jun 24, 2004

Yo do not need two valves....PERIOD....Paul.

MustangPaul · Jun 24, 2004

Ron--Gotcha. I wonder if I can put it somewhere where it won't be too visible.

Ah well. . . . Decisions, decisions!

Thanks!

--P

Ronstang · Jun 24, 2004

There is a way to accomplish the blocking of the coolant flow to the heater core without having an ugly valve installed. If you have one of those Prestone flush tees installed then you simply have to buy another tee and fill it up with heat stable epoxy or find some other way to block it off and install this tee in place of the normal one during the summer. You could just replace the tee with a piece of solid barstock also if you like. For that stealth look you cam make a plug out of copper that fits up inside the hose right where it attaches to the intake manifold....just make sure you drill and tap a hole (not all the way thru of cours) in the end that you will be able to see up in the hose so you can screw a long bolt in there for extraction during the winter months.

D.Hearne · Jun 25, 2004

Ronstang said:
Yo do not need two valves....PERIOD....Paul.

Apparently you didn't read the reason for using two valves instead of one. When the heater core bust's loose from the engine being rev'd, two valves are always better than one. One will only prevent the coolant from circulating when the engine's running, if there's a leak in the heater core ( and this happens frequetly) one valve won't stop it. But if you insist on using one valve, it's your car ( and carpet) go ahead and do it. Every heavy truck I've driven had two shut off valves for the heater core circuits( most have two circuits, cab and sleeper ) just for this reason. The valves are realatively cheap, so it makes good sense to use two.

WORTH · Jun 25, 2004

A couple of things you may want to keep in mind. Ford doesn't use HCV's. This means the water is always circulating out the manifold fitting and into the waterpump threw the heater hoses.

If you want to shut off the heater buy an "H" fitting and install it between the 2 heater hoses and put your shutoff valve on the heater side of the "H". That way the water will always circulate even if the valve is shut off.

ALso for those cold summer nights, you may want to use a cable operated HCV and use a choke cable to run it from inside.

Just a thought..

Max Power · Jun 25, 2004

Hot coolant won't flow into the core if it can't flow out. And with a new core, I don't think there is really any risk of over pressurizing the core. In 25 years of working on fords, I have never seen it.

My biggest problem would be an unsightly cably mounted in the dash. I would just bypass it under the hood with a flush tee, then reconnect in the winter.

L8knight · Jun 25, 2004

Well I tried Napa last night and they didn't have anything I could use. So I am going to check out the links posted within this thread and see if I can get something on order.

I'm now 2nd guessing whether to do a straight shutoff or the H system (also mentioned above). Oh the confusion! In-let side, outlet side, one valve or two valves, to H or not to H!

WORTH · Jun 25, 2004

L8knight said:
Well I tried Napa last night and they didn't have anything I could use. So I am going to check out the links posted within this thread and see if I can get something on order.

I'm now 2nd guessing whether to do a straight shutoff or the H system (also mentioned above). Oh the confusion! In-let side, outlet side, one valve or two valves, to H or not to H!

ALlow me to simplify; these are Car Qwest part #'s but I think NAPA is the same #

5/8" "H" = 278912
5/8" manual HCV = 277950
5/8" cable operated HCV = 277824

and it doesn't matter if you run the valve on the inlet or the outlet as long as it is between the "H" and the heater.

Heater Host Shut-off Valve

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