Replaced heater valve and cable, now no heat?

As the title states, I replaced my heater valve because the other was leaking around the small screw (parts store valve) and replaced the control cable because it was binding and not allowing the temperature control to turn. Before, the heater was working fine. It would heat you out of the cab. However, now that I replaced the cable and valve the best it will do is luke warm. Granted the heater hasn't been used in 8-9 months. I disconnected the cable and cut the valve to off for the summer..but even last winter when the cable was not working, I disconnected it and controlled the valve manually depending on the outside temperature.

So far I've done all I know to do. I've tried burping the system to see if I may have cause an air pocket when replacing the valve, but no air bubbles seemed to escape and little to no change in the heater temperature. While installing the cable and the dash was apart, I did work the temperature control and the vent controls to see if everything is working because I have had a problem with air not coming out of the middle vents very hard. With the temperature control set to heat, the valve is all the way on. Ive tried looking at the blend door and all seems to be working but its rather hard to tell. Did I miss a step when installing the cable? Or possibly cause a cable not to be fully engaging by tinkering with the temperature and vent control without everything installed?

 

Did you check that the valve is fully open/closed from the engine bay? If you clamp the cable in the wrong location it doesn't get full travel.

 

If you've manually moved the blend valve to open under the hood on the firewall, you should be able to feel hot coolant moving through the hoses. You should be able to feel hot hose going into the firewall for the heater core as well. Strictly based off what you describe and share, I'm leaning towards air still in coolant system. But checking those hoses I mention will help us clear that up.

 

Yes, I have. With the control set all the way to heat, the valve it fully in the closed position. But I’m going to double check it one more time since it’s easily accessible.

I’ll double check this as well. I know I felt the input hose, it seemed to be hot.

Also, when I installed the new cable I undid one or two of the other control cables. I believe one was for the vent control. I don’t remember what was the other. I also know that there is another cable attached on the under side of the temperature control. When I installed the new heater valve cable, would it be possible that the other cable wasn’t in the right position and limiting the range of motion so that the blend door isn’t fully closing?

 

Quite possible the outside of the heater core is so dirty no heat transfer occurs.

Like it was said you should be able to feel both heater hoses about the same temperature .

For the best heat fresh air not recirculate !

 

When I took apart my dash on my 84 the heater core was so caked with debris if didn't get very hot. Plus I found a rag behind the top vents. Once everything is all finished up it should be nice and hot and flow great.

 

A dirty heater core could be a very good possibility. It was so incredibly dry and dusty over the summer that it would be surprising. But even cleaning would require taking the dash back apart, correct?

 

Yes. A real PITA so I would exhaust all other possibilities first.

 

since I just had to take the whole thing apart to replace the cable, taking it apart again isn’t something I’m looking forward to or wanting to do

 

Any chance you've got air in the system?

 

That was my initial thought. I tried to burp it earlier today but no results...

 

Does the hose to the valve and to the core get hot?

 

You may have to plant that front up on a nice hill to get all the air out if any.

 

the inlet and outlet hose to the valve are hot when the temp control is set to heat. The hose coming back out of the core to circulate the coolant seems hot as well. Possibly not as hot as the other hoses, but still hot.

Agreed, I set it up on a set of ramps when trying to burp it. Don’t know how much more I would be able to get it.

 

Just verifying if the dial is all the way cold and heater valve is fully closed no coolant should circulate through the heater core correct? Mine has a small leak and I’ve noticed both hoses coming out of the core are always hot even when it’s on full cold setting and valve is shut.

 

This I have not verified. I know that the valve is going through the full range of motion, and that in the heat setting both hoses are hot, and the return off of the heater core it hot. But i have not checked to see if the outlet side of the valve is cold when the valve is off. I assume that it would be since the AC is still blowing just as cold as it has been, no change there.

However, what led me to replace the valve itself was a small leak around the screw that holds the arm on. I cant remember if it was leaking when the valve was off, or if it was leaking before it got up to operating temps with the valve open. Either way, it would start out as a fast drip that would leave a noticeably small puddle on the ground

 

Both hoses will get up to engine temperature given enough time .

As heat is transferred to the coolant

 

If this is not a typo, there could be your problem.

 

my bad, it was a typo. With it set to heat the valve is fully open. With is set to cold the valve is closing

 

Just FYI, didn't see it mentioned, but the blend valve even when fully closed, set to cold, has built in tolerance so that it doesn't fully shut off the coolant flow. You still want some trickling through the heater core, and that's why the valve is designed to allow that.