BearKiller

Which direction does the coolant flow through the heater-hoses??

Out of the engine at the top and back in at the bottom; or, out at the bottom and back in at the top??

Also, I am going to install a heater-core shut-off in my heater-hoses.

Do I need to plumb in a "U" for the coolant to still cycle through the hoses, bypassing the heater-core; or, can I simply put a cut-off in one hose?? which hose??

Thanks.

JD730

It should flow out of the head and then back too the bottom, otherwise you won't get any heat. And the shut offs are usually in the hose coming from the head and there is no bypass.

Take a look at your wife's truck, thats the way dodge set it up.

BearKiller

Thanks.

So I can just put a cut-off valve in the top hose and that will do the trick??

Thanks.

Bill Tomlinson

I sure hope so. That is what I did about six months ago. It really makes a difference come AC time which is less than six months away up north here.

bgilbert

Shut off/ball valve in the hose nearest the passenger side.

Ace

I'm having trouble understanding why you guys are putting valves in the heater hose. Isn't the temp slider on the dash connected to a vacuum controlled modulator in the heater hose? Otherwise known as a "valve."

wannadiesel

That valve is open except when the slider is in the "OFF" and "MAX A/C" positions. Air temp is controlled by a blend door.

Bill Tomlinson

Our AC units partially modulate by adding hot air. It is much better to just shut off the hot water and hot air in the summer. Unless of course you want to use the water and cooling capacity of the heater core etc to increase your cooling capacity. (I have had to do it in an old volvo which I ran without a fan and got stuck in a traffic jam on a warm late winter day)

Ace

I was glad to hear it works that way because my coolant filter will be getting at least some circulation in the summer, depending on whether or not I'm using the A/C, I guess.

bgilbert

Yep but like other 100 year old vacuum actuated trash, it can be a POS. Many are well known to fail. Cancel it, slap in a hardware store shutoff valve.