Shut off valve for heater hose

[ls1nova71]

I see, and yes the older ones will do that. You need a genIV A/C unit, they have electric servo shut off valves and stay where you put them as, but probably a little late for that now. My car will cool the heater core pretty quickly though, and having the ability to turn the heat on whenthe air is on is helpful if the evaporator starts to freeze up which they are known for doing. As for blocking the hose fittings, I wouldn't worry about it, ive put 100's of thousands of miles on swaps with valves that completely shut the water flow off and never had a problem.