Heater hose set up

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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ghiltgen
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Heater hose set up

Post by ghiltgen » Fri May 21, 2021 7:05 pm

My cj2a is over heating and I am wonder if it is related to how the heater hoses are hooked up. The water pump has 2 ports, at roughly 10 and 2 o’clock position. One heater hose comes off at the 10 o’clock position, the 2 o’clock port is capped. The other heater hose goes to the cylinder head.
When the engine temp gets to 200 and higher, I can’t feel hot water going thru the hose from the thermostat housing to the radiator and then it gets to the point of over heating.
I removed the thermostat and put it in a pot of water with a thermometer and it opens at 180 degrees (don’t tell my wife I am testing jeep parts in the kitchen!). my conclusion is that that water flow won’t go into to the thermostat housing, and therefore the radiator, because of the flow direction thru the head due to the hose arrangement.
Dose this sound plausible? What is the best arrangement for the heater hoses?

Thanks,
ghiltgen
1943 MB SN 226406
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GPW 127386
1948 CJ2A
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Bruce W
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Re: Heater hose set up

Post by Bruce W » Sat May 22, 2021 7:08 am

That is the correct arrangement for the heater hoses. Whether they are there or not, whether there is a heater core in the system or it’s been bypassed, or if the ports have been plugged, will have very little effect on your cooling system, and definitely will not cause overheating. You’ve got another problem somewhere, but that ain’t it.
BW
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Rus Curtis
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Re: Heater hose set up

Post by Rus Curtis » Sat May 22, 2021 7:43 am

ghiltgen,
As Bruce explains, the heater is optional.

To visualize the flow, the radiator takes hot water in through the top. Cooled fluid exits the bottom and goes directly into the pump. The pump pulls water into the engine. The hoses to the heater could be connected either way and would work normally (its just a small radiator).

I have a 3B with an F-head and that smaller port on the pump was used as a bypass that connected to another fitting on the head directly above.

Back to the overheating. I agree with Bruce, the heater isn't causing this. The one clue is you don't feel hot water in the upper (return) hose connected to the thermostat housing. On the 2A Forum, there are posts that describe two different thermostat configurations. I'm not familiar with the bellows type and our 3B thermostats don't need a spacer.

Details are missing. Is this a new thermostat? Did you add a small hole in this new thermostat? Old thermostat? How long since flushing the system? How often did you cycle the thermostat in the kitchen? Have you run the engine/circulated coolant without a thermostat?
Rus Curtis
'54 CJ-3B
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ghiltgen
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Re: Heater hose set up

Post by ghiltgen » Mon May 24, 2021 6:41 pm

I’m not sure how two threads got started on this, but thanks for the advise. I considered drilling a hole in the thermostat but didn’t. I changed the thermostat position and placed it on the head the the spacer above. With it the over way where the spacer goes against head and the thermostat is in the top of the housing if the coolant level is low the bottom of the thermostat won’t be bathed in the coolant and may not sense the temperature increase. Anyway, after I flushed the radiator I found multiple small leaks so I believe there was air under the thermostat and the coolant was low. probably the leaks weren’t noticeable until the scale was removed. So with a radiator swap and new thermostat position it now works well, the thermostlat opens at 180 degrees and I can feel heat in the upper hose.l
The “universal “ jeep manual didn’t have anything I could find on the position of the thermostat.
ghiltgen
1943 MB SN 226406
Veteran Award, Motorpool Class 2021
GPW 127386
1948 CJ2A
MVPA member 36543


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