Heater core/valve

[Sgt Art]

There is a vacuum controlled valve that screws into the rear of the intake manifold. I'm guessing this controls the flow of coolant through the heater core. Is it absolutely necessary? Could I simply replace it with a fitting and run a piece of heater hose to the heater core and eliminate this valve? Seems by eliminating it, I'd have one less thing to go wrong. Heater puts out heat, so I guess it's working properly.

[Oldsmaniac]

That device is known as a heater control valve. It is used on AC cars tp prevent hot water from circulating thru the heater core when the AC is on or no heat is called for. If you look at the end you will see it is restricted down to a much smaller hole....this reduces the pressure that the heater core will see and thus helps reduce the chance of blowing a hole in the heater core. If your AC isnt working you can do away with it but the pipe shouuld have that restriction. Ive run cars with just a pipe there and no restrictor and have had no trouble.