[scld1354]

I just swapped a Performer intake and Qjet (rebuilt with Cliff's kit) into a 65 GP. I found a decent stock Q-jet air cleaner and am trying to get the ThermAC system to work properly.

The vacuum motor that controls the flap works and holds vacuum. I am wondering about the temp sensor that sits on the air cleaner. I've seen it called a thermal vacuum switch, a ThermAC switch, an air cleaner temp sensor, among other things.

As I understand, these are supposed to allow vacuum to flow through them when cold (remain open) and shut off the vacuum when warm (close). I tested the one that came on the air cleaner and it didn't hold vacuum when it was cold. I bought a new one and it does the same thing. It holds enough vacuum to actuate the motor that controls the flap.

Are these supposed to hold vacuum or are they a designed vacuum leak?

[TedRamAirII]

Vacuum should flow through the valve when cold, it closes the door to allow warm air from the Exhaust manifold. When air temp is 85f or below, the door should be closed. 85-110f the door should be start opening and over 128f the door fully open. There is a small vac leak when the door is fully open, but not enough to hurt anything.