heater core bypass question

[rockbender]

I would like to install a simple heater core bypass / shutoff valve. I've read the tech article but don't really want to get that complex if possible. My question is, can I just install a simple 1/4 turn ball valve in line on the intake side only going to the heater core? Will this build excess pressure, ie - do I need to make a loop in the system that bypasses the core so coolant is still flowing?

Also, which heater hose is the inlet - the one coming from the passenger side of the block or the one on the front?

 

[argve]

Yep the one coming off the head on the passengers side is hot line that supplies the heater core and you will be just fine closing it off.

 

[stumiister]

What is the purpose in putting a shutoff vlave?
If it was my truck I would be doing if the heater core started leaking all I would have to do is turn the valve off but I would put 2 valves in one at the passenger side head fitting and the other on the water pump fitting that way if a hose blew or the core started leaking then I would turn the valves off and add more coolant.
There is no need to make a loop and there wouldnt be any extra pressure in the cooling system.
On the big trucks I tell the drivers to turn the water valves off to make the A/C blow colder since the older trucks have problems with blendoor systems.

 

[franklin2]

I believe that's the main reason, to help the A/C system. But I would not call the ranger valve install complex. The valve is not expensive at all, and goes right into the hoses after you cut them.

 

[rockbender]

Thanks guys. Yes, the purpose is most certainly to get the AC (once working) to blow cooler and also just to have vent air that isn't slightly heated when the AC is off. I think my blend door is functioning properly (I just got a close up view of it while replacing the AC evaporator), but the lack of a heater control valve means that the heater box is always hot. On a van, the heater box sits right above the passengers feet and since I'm battling engine heat through the doghouse as well, every little bit will help.

With the valve in place, it would make it much easier to do a field fix if I needed to bypass the heater core, but that isn't my primary objective here.

 

[MIDNIGHT RIDER]

A manual ball-cut-off valve will positively stop the hot coolant from entering the cab.

The factory-issue vacuum operated ones only cut the flow about 2/3 when they are working.

We have manual valves on everything around here.

The wife's truck (Dodge/Cummins) had a functioning vacuum valve; I replaced it with a manual valve and her dash-temps dropped from 50-ish to the very low 30s in humid 90*-plus weather.

I highly recommend them.