Water Pump / Head Bypass Debate?

[Kendog]

Is there a final answer for the requirement of the bypass hose connecting the water pump to the back of the head if the truck does not have a heater? My truck does have it piped in by the PO, but I don't understand why.

[Carls_jeep]

There is no bypass hose on the L134. If you have a heater, one side of the heater goes to a fitting in the head and the other side goes to a fitting in the water pump. That provides a water flow to the heater.

[Gunslinger]

I can't imagine why the PO would have plumbed that in.  When I got my Jeep the heater was not piped, the hole in the block was plugged as was the outlet on the water pump.  Ran it like that for a couple years until I got the heater re-built, no problems occurred.  I've got to think the PO didn't know what it was for and took a fling at hooking it up, just in case....

[Carls_jeep]

When I got my Jeep the heater was hooked up. I didn't want to use it so I pulled the hoses and jumped one of them across the heater outlets and removed the fittings from the head and water pump.

I suspect the past owner of Kendog's Jeep didn't know how or didn't want to remove the fittings. The problem with it plumbed that way is it would be hard for the thermostat to do it's job. He should remove the hose and fittings and plug them up.

[Kendog]

So I will plug them,,, and without wanting to sound lazy and info abusive,,, but I'd like to purchase two plugs before getting back to the Willys project,,, are those plugs a standard pipe thread/size or something unique? research suggests 3/8" Pipe.(?)

I will be not be getting to my project jeep or parts jeeps until the weekend to check for donor plugs, etc.

Thank you. Ken

[Gunslinger]

3/8" inch NPT sounds right for the water pump, but the fitting in the head might be half.  Ther'e cheap, buy plenty