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My M came with a heater installed under passenger side dash. Not sure where it originally came from but it's def military. It's not wired yet so I gotta check and make sure it's 24 volt. It has inlet and outlet tubes for heater hoses. My question is what are the best spots to pickup feed and return lines. Theres a pipe plug on the top of the water pump and another nearby on the top of the bottom radiator hose metal tube. Also a plug at the back of the cylinder head.

Hi Bill,

I'm not saying this is wrong or right......but this is how the heater was hooked up in my AF M37 by the previous owner.

regards,
bob



DSC02723 by w30bob, on Flickr


DSC02385 by w30bob, on Flickr

On the back of the cylinder head, there is a 1/2" NPT port labeled "heater". Wouldn't that be a better place to pick up hot coolant, while shortening one of your hoses?

x2

all my 251 heads have a port marked heater located above #6 on the passenger side. the water from the rad is pumped from the lower rad hose down the distribution tube around the cylinders and valves then it travels to the back of the block up to the head then to the thermostat and up the upper rad hose. I plumbed my heater from the heater port on the head then through the heater core to the inlet on the lower rad hose were it mixes with the cold water and back to the pump.

I used the head plug and the thermostat plug for mine-my return hose didn't have the nipple.
Gary

GOOD MORNING, I also used the head plug. v/o #6 and the return to the thermo housing. I put a ball valve at the head connection. keeps the hot water away from the heater during the summer.
bob

Thank you everyone. I think the head plug and thermo plug is the way to go. Also planned to install ball valve to shut off flow for summer months. Can easily install ball valve into head. Thanks guys.

Sorry, I meant from the head plug, thru heater core then to lower hose fitting.

bill monahan wrote:Sorry, I meant from the head plug, thru heater core then to lower hose fitting.

Could I see a photograph of your heater? I'm trying to Id my heater as well, and so far I know it isnt an M151 or M35 heater!



-T

I'll send a pix if I can figure out how, lol.

Ok, now that I know how to hook up my hoses, I'd like to hook up some kind of switch to control fan speed. My heater is definitely military and the fan runs well with a 24volt lead and half as fast with a 12volt tap. Some type of rotary rheostat is in order but I don't know what wattage I should look for. Anybody have any ideas ?

Hi Bill,
I ran a hot wire off my ignition to an on/off switch then to the heater fan. The unit is self-grounded and works w/o a rheostat.
Gary

Guess I can regulate the heat by just turning a switch on and off. I shouldn't over think these things. Thanks.

GOOD MORNING, I bought my heater from JC Whitney, it has a two speed fan. works great. My M has a soft top, on cold days the low speed fan keeps the cab warm. on really really cold days the high speed fan works good. A lot of drafts come thru in various locations. I would think that if you wanted to control the heat output an adjustable valve that could be controlled from the cab would be your best bet. I have seen them on e/bay in the M37 section.
GOOD LUCK
BOB