Coolant Leak from GP controller

[D_Fresh361]

on the way to work this morning I smelt burning coolant. Investigated when I got to work. Coolant is spewing out of the GP controller. Running manual GP set up so controller is irrelevant to me now. What am I looking at here?

Thanks

 

[mblaney]

No coolant going to the GP controller so it is either being sprayed from somewhere else or it isn't coolant.

How much is spewing? Burning or steaming?

 

[snicklas]

No coolant going to the GP controller so it is either being sprayed from somewhere else or it isn't coolant.

How much is spewing? Burning or steaming?

86 and older have a different controller. It’s a 2 part system with a controller that screws into the drivers side head, by the firewall. It’s a simple bi-metal switch that like to fail on, and fry plugs. The controller activates a second solenoid on the passenger fender that runs the plugs.

 

[snicklas]

on the way to work this morning I smelt burning coolant. Investigated when I got to work. Coolant is spewing out of the GP controller. Running manual GP set up so controller is irrelevant to me now. What am I looking at here?

Thanks

I think it’s a pipe thread. Maybe someone here has one out and can tell you the size, or if you have another vehicle, pull the controller and match it up at the hardware store. The solid state controller 7.3 just have this hole plugged. Actually I the front of the passenger head (they use the same head , not a left and right) the same hole already has a plug in it.

 

[icanfixall]

Those screw in controllers are national pipe threads. They have to be the tapered thread so they can seal for no leaks. Am not sure what the size is but they are all the same in both heads. Our engines do not have a left and right head. Both are cut or machined exactly the same.

 

[riphip]

I believe that is a 1/2" NPT. I replaced old controller with New Style (87+) & use that port for my Coolant Temp Guage

 

[D_Fresh361]

Well update guys. Got back to the truck after work and managed to break off the GP controller in the head while attempting removal. My experience with easy outs and this soft bi-metal mentioned that the controller is made out of tells me this is going to be a major PIA fix. Planning on plugging with a pipe plug once the rest of GP controller is removed. Easy out just gonna cut right through the soft material. I swear if some of the controller body had stayed I would just JB weld over the top of it with high temp and move on since it would still be removable if needed to be one day.

Gotta get this pig back on the road though whatever I choose to do. Boss wants me to pull the gooseneck out to the ranch tomorrow.

Right meow that ain't happenin.

 

[D_Fresh361]

I believe that is a 1/2" NPT. I replaced old controller with New Style (87+) & use that port for my Coolant Temp Guage

Using the existing port for a coolant gauge is a great idea! This will be the route I will eventually take!

 

[D_Fresh361]

Using the existing port for a coolant gauge is a great idea! This will be the route I will eventually take!

Are we sure on the thread size for the GPC so I know what size plug to get?

 

[austin92]

I will check for sure when I get home after work this morning. I have a controller on the shelf and a mountain of pipe fittings I can test it in. Harbor freight has a pipe nipple specific extractor set that would probably work well for you. I think it’s 10$ and covers 1/8 through 1”


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[IDIBRONCO]

Actually I the front of the passenger head (they use the same head , not a left and right) the same hole already has a plug in it.

Isn't that where the fast idle switch is at?

 

[snicklas]

Isn't that where the fast idle switch is at?

Not sure, not be down to the thermostat yet. I know it's down in the area of the thermostat housing, but not sure if it's in the head.

I think @IDIoit has some pictures in that area in the Ranchero thread....

 

[IDIBRONCO]

I'm fairly certain that it's in that same port. There's not another port in that location.

 

[IDIoit]

yes, its the same port.
passenger side is the high idle temp switch
driver rear is the 6.9 controller for the plugs.
1/2" NPT

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[austin92]

Double checked, gpc is definitely 1/2 npt


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