I've read several posts about hot air always coming through the vents. There are also several posts where people bypassed the heater core to solve it. I was thinking of simply putting a on / off valve in the heater hose coming from the water pump going into the heater core. My question is what about the return line? Does that get used to help in cooling the engine, or is it's only purpose a return?

BTW, I took the heater box apart to see if the heater door was opening and closing and it was. This looks like one of the dumbest designs ever. With the door closed the air doesn't go THOUGH the core, but it goes right past it, so the air will still get heated up. That's gotta be the root of the hot air problem.

Thanks.

 

Anyone? Even an overview of the coolant flow would help... Does the coolant coming back from the heater core cool the engine?

Thanks.