Could my heater control valve be stuck "open"?

Posted By: rnch

Could my heater control valve be stuck "open"? - 05/26/13 07:00 PM

Even with the dashboard temperature lever all the way to the left, the heater hoses on both sides of the heater control valve (located next to the right side valve cover)feel like the same temperature after the 318 motor reaches operating temperature.

Shouldn't one side be cold...or at least cooler than the other side?

It looks like 1985 factory original equipment.....everything else on this truck was.

Posted By: bigblock340power

Re: Could my heater control valve be stuck "open"? - 05/27/13 12:55 PM

Quote:

Even with the dashboard temperature lever all the way to the left, the heater hoses on both sides of the heater control valve (located next to the right side valve cover)feel like the same temperature after the 318 motor reaches operating temperature.

Shouldn't one side be cold...or at least cooler than the other side?

It looks like 1985 factory original equipment.....everything else on this truck was.

Are you getting heat out of some part of your venting inside the truck with the temp. lever all the way to the left? I had that problem too. My problem was the cable came off the lever tang. But when I put it back on the cable bent. The heater valve on the pass. fender was gummed up and hard to move. I took it off, bead blasted it, and WD-40'd it. Works great now. Also found a new cable.
I'm wondering what year truck you have? Mine's a '76, 360 with A/C. The valves are different with/without A/C.
Mine.

Also, get one of these for the valve. Works better than the rolled metal one.

Posted By: basketcase

Re: Could my heater control valve be stuck "open"? - 05/27/13 04:09 PM

Quote:

It looks like 1985 factory original equipment.....everything else on this truck was.

my '87 & '88 are vacum operated, but they both had AC. not sure if the non AC trucks were vacum as well.

Posted By: nytemuvr

Re: Could my heater control valve be stuck "open"? - 06/03/13 09:14 PM

One thing for sure is the heater hose is about ready to go as they're over tightened(rubber is coming though the holes on the hose clamp) and the top rubber hose is bulged and is ready to blow. The black control cable needs to stay in one spot and it looks as though it's not squeezed together to hold it in place(the 2 little holes need to be tightened together to hold the cable in place).Just a heads up.

Posted By: stumpy

Re: Could my heater control valve be stuck "open"? - 06/03/13 09:43 PM

I agree about the hoses but the clamp doesn't need the holes squeezed together because it has teeth that hold the cable.

Posted By: Challenger 1

Re: Could my heater control valve be stuck "open"? - 06/04/13 01:15 AM

They corrode and leak inside, real common problem with some water valves. Especially older ones. Take a clamp and clamp off one of your hoses and see if there is any difference. Does not matter which one, just stop the flow of hot water in or out of the heater box. See if it's any cooler inside while your driving. I'm betting it's leaking internally.

I have some vehicles in my work fleet that I clamp off hoses in the spring and take off the clamps in the fall. Cheaper that replacing water valves that don't last long enough. They don't leak externally but do internally.

I use 2 pieces of 1/2" aluminum angle that I put 2 1/4-20 bolts through to hold them together. It don't hurt the rubber hose.
The picture above:
Those hoses above looked like they were exposed to oil? That's what causes them to expand like that and I would replace them soon.

Edit:Picture, this clamp can do both hoses.

Posted By: savoy64

Re: Could my heater control valve be stuck "open"? - 06/06/13 04:17 AM

i just put a new valve on my 64---found out when it is shut off the lever doesnt go all the way to the stop---it is supposted to stop just short-- covering the OFF stamped on the valve--mine wasnt shutting off and i took it back off and looked through the hose end to see that if your set it to touch the stop that the valve was slightly open--backed it up to cover the OFF and wallah the valve was closed....bob