Heater hoses on '56 Fairlane

[Hot Rod Reverend]

There were two options for coolant control feeding the heater core. The most often supplied valve was one that was vacuum controlled and was attached to the intake manifold. A long vacuum tube went back through the firewall to the heater controls.

The "nicer" valve was the one you are describing on the firewall. It actually has a capillary tube that was in the heater plenum to sense the heat coming from the heater core and fluctuate the level of coolant (and therefore temperature) coming through the heater core. Of course, you need to be a little bit of a magician to know the temperature degrees associated with the dash lever that controlled the setting. You had a Low and a High setting with the word TEMP in between.