Well since I have never seen one like that, I can't give you any kind of real insight but I can take a stab at a guess... That thing would only be closed on a cold engine so the vacuume pot there would either have to apply vacuume to close it or apply vacuume to open it (my guess is vacuume to close so if it failed it would be open). Either way, there would have to be some vacuume switching device that switched when the temp changed. I would look for something that looks like a temp sensor screwed into the intake that has some vacuume fittings on it or a solenoid that has some vacuume fittings on it. I would guess that there would be two fittings, one would go to manifold vacuume and the other to the vacuume pot on the heat riser. <<<<<Lotta explanation for someone who has no idea what the truth is huh?
