heater shutoff valve location

tom36 · February 20, 2004, 03:12:51 PM

I'm plumbing a heater into the '36 Cabriolet with the nailhead, and can't make up my mind as to which hose to put the shutoff valve in-- the hose off the water pump or the one off the block. Common sense tells me it doesn't make much difference as the water won't circulate thru the core with the valve off, but, inquiring minds want to know. Any thoughts? Tom.. :?:

mopar2dr · February 20, 2004, 04:50:20 PM

I put mine in the hose from the engine. This is the hot water supply(on a Mopar). Even a small amount of hot water going through that heater will make your passenger grumpy in hot weather. I'm wanting to upgrade my heater and have been thinking of checking the local farm store. Figure if it can heat a Deere it can heat a Dodge.

bowtietillidie · February 20, 2004, 08:27:23 PM

Quote from: "tom36"I'm plumbing a heater into the '36 Cabriolet with the nailhead, and can't make up my mind as to which hose to put the shutoff valve in-- the hose off the water pump or the one off the block. Common sense tells me it doesn't make much difference as the water won't circulate thru the core with the valve off, but, inquiring minds want to know. Any thoughts? Tom.. :?:

Here is a thought Put the valve off the line that supplys the heater core.
(Reason) with the pressure line shut off , If the heater's core ruptures
you won't have full pump pressure pushing collant in to the cock pit. This fact plus the pressure that builds as collant heats up causes a very dangerous condition. This way stops circulation and now the water pump is now trying to pull water out of the heater . Understand I am not saying that collant will not get in the car I am just saying that it won't be comming like it is comming out of a four inch fire hose. If you ever had a drag car split a heater core this will become INSTANTLY clear :cry:

tom36 · February 21, 2004, 05:08:06 PM

Makes sense--I'll put it in the block side hose. Thanks guys. Tom..

Sean · February 22, 2004, 05:16:29 PM

Where do you get those Valves? I need to put one on my Truck. My heater just barely keeps you warm in the Winter, but it'll flat out roast you in the summer even though its supposed to be off. Last year I just looped the Heater hose.

tom36 · February 22, 2004, 05:39:06 PM

Quote from: "Sean"Where do you get those Valves? I need to put one on my Truck. My heater just barely keeps you warm in the Winter, but it'll flat out roast you in the summer even though its supposed to be off. Last year I just looped the Heater hose.

NAPA has all different kinds. Get the counter person to let you look thru the book with heater valves and pictures of valves and take your pick. Some are vacuum operated, others cable. Tom..

bowtietillidie · February 22, 2004, 06:19:19 PM

Quote from: "Sean"Where do you get those Valves? I need to put one on my Truck. My heater just barely keeps you warm in the Winter, but it'll flat out roast you in the summer even though its supposed to be off. Last year I just looped the Heater hose.

Sean: Since I have had a few automotive valves fail me, I use valves from a pluming supply house . I use Ball type valves that are rebuildable
they cost quite a bit more an are ugly. I usualy change some plumbing around so as to put them out of direct sight. I have never had a ball valve fail. I have had two failures with heater related incenadents both
were because of automotive replacemant parts . No mater how hard I try I just can't become friends with Hot engine coolant !!!!!!!

Burned feet and legs/ Bowtietillidie

Sean · February 22, 2004, 06:22:27 PM

I have a couple of 3/4" Stainless ball valves left over from a Job at work. I guess I could find hose barbs to screw in the ends of one of them. Kind of heavy though.

Pope Downunder · February 22, 2004, 08:29:28 PM

Quote from: "Sean"I have a couple of 3/4" Stainless ball valves left over from a Job at work. I guess I could find hose barbs to screw in the ends of one of them. Kind of heavy though.

I used the standard cable type, although I have seen the ball-valves you talk of here that I will use next time, as they are more positive, and less likely to fail. You can get them here at welding gas supply outlets. They are compact, silver, with a black plastic knob.

enjenjo · February 22, 2004, 08:49:39 PM

You can get the valves in brass too, from a heavy truck parts supply. they come in straight, 45 degree and 90 degree.