I was trying to troubleshoot the vent system in my car, and found an intersting device in front of the firewall. On my 1990 GT, I removed the air filter housing, and directly below it, was a plastic valve. Those hose seemed to come from the back of the engine block, go through the ontrol valve and through tthe firewall. There is a side below, where a small diameter hose is attached.

What is this valve used for, and what flows through it.

- Matt

 

Heater control valve. Allows or blocks hot water to the heater core.