Heater Core Valve Issues

[DreadPirateJon]

I recently replaced my heater core valve with a new OEM unit as I had read about people having the plastic inlets break leaving them stranded and wanted get ahead of that failure.

But now I have no control over the amount of the heat, it is either off or full, so I am having to either drive with windows cracked or modulate the heater as I drive.

Could this just be the result of a bubble in the system? Because I cant really think of anything else.

 

[alumarine]

When you adjust the temperature in the cab does it operate the valve through it's range of motion?

 

[MaineRunna]

Toyotas also use an air blend door. Sounds like the cable might be off and it's in the hot position, so the only way to make it cold is to set it all the way on cold, closing the water valve.

 

[nissanh]

Did you mount the outer cable in it's original location at the heater valve mounting bracket?

 

[DreadPirateJon]

When you adjust the temperature in the cab does it operate the valve through it's range of motion?

It does, forgot to mention that in the original post. I disconnected the wire and moved the valve by hand through its motion, then hooked it back up a verified the range with the interior control.

 

[DreadPirateJon]

Did you mount the outer cable in it's original location at the heater valve mounting bracket?

I did, one of the benefits of a rusty truck (besides the extra frame flex) is that it left very easy to see marks for hooking it back up.

 

[DreadPirateJon]

Toyotas also use an air blend door. Sounds like the cable might be off and it's in the hot position, so the only way to make it cold is to set it all the way on cold, closing the water valve.

Hmm, I had not considered that. I'll give that a look and see what I can find. The switch over from cold to hot happens about in the middle of the range of motion though.