Help with Heater core problem on my M1123

[The Iron Horse]

Hey guys,

I am trying to understand why my heater doesn't work on my M1123. I never managed to get it to work since I got the vehicle from GovPlanet.

Not sure If am missing any secret manual shutoff valve anywhere... or what?

It looks like the shutoff valve connected to the pull out knob is turning fine.

Maybe the heater core is clogged and needs a good flush cleanup?

I appreciate the help as always!

Thank you

 

[Lothar]

It's not too much work to remove the heater core. I recently replaced mine. If you think its clogged up, I would remove it and try running water through it. Also, since it's out you can pressure it up and check for leaks with some soapy water. The older they are, the more prone to leaking. I was a welder in the military and repairing radiators was a large part of my work. These things are cheap and small so easier to just replace them.

 

[The Iron Horse]

Yes, will do. I will try to run some water through it and see what happens. I just didn't know if there is some kind of a manual shutoff I did not know about. I could not find anything in the TM about a manual shutoff.

Thank you very much!

 

[Lothar]

The valve you already mentioned is the only shutoff. You can check to see if it is working correctly when the core is out of the way.

 

[Action]

fast check is to just pull the 2 hoses off in the engine compartment. hook a spare hose to one of the core tubes and see if you can blow any water out the other. i wouldn't put anything more than about 15-16 psi thru it.

 

[The Iron Horse]

Yes, that was my plan. I will try and give you guys an update.
As always, I appreciate your help. Thank you!

 

[juanprado]

There is the out side possibility that a shut off was installed or hoses tied together as a quick fix around in case of a leak.

Also look at the heater control valve to make sure it is operating correctly.

Pop the hood open and give it a good look see over all the heater components

 

[AAVP7]

Also look at the heater control valve to make sure it is operating correctly.

I once stumbled upon a heater control valve that looked completely identical, but worked "the other way around". With the knob pushed in, the valve was open and let hot water through, and when you pulled the knob out, it closed. Probably a chinese knockoff, and while copying everything, they had the blueprint upside down....

 

[86humv]

I once stumbled upon a heater control valve that looked completely identical, but worked "the other way around". With the knob pushed in, the valve was open and let hot water through, and when you pulled the knob out, it closed. Probably a chinese knockoff, and while copying everything, they had the blueprint upside down....

I've had the valves that work opposite ...they are 2.5, or 5 ton truck valves.

 

[The Iron Horse]

Thank you guys! I will check and report back with an update

 

[The Iron Horse]

Hey guys,

I cleared the heater core still in the vehicle with the hose from both directions and it worked! A lot of stuff and debris drained out and some small stones, probably buildup of corrosion and rust.

Besides that everything looked great! I was really surprised how clean the coolant was considering last time it was replaced was probably 12 years ago in 09 according to a note I found on the engine.

Thank you very much for all the help! Me and the wife are super happy to have heat in the cabin. Especially my wife!

 

[KS_Patriot]

Well done. It looks like it doesn't take much to plug'em up.

 

[The Iron Horse]

Thank you!