Vetteman61

iTrader: (1)

I want to put a shut off valve on my heater core for the summer. I don't mind having a manual shut off valve, however it would be pretty easy to install a heater control valve. My experience is a heater control valve is another extra level of complexity and I prefer to keep things as simple as possible.

What are the compelling reasons to install a heater control valve over a manual shut off valve?

Thanks,
Brandon

Michael Yount

iTrader: (1)

If you need to be able to modulate it from inside the car then you need a control valve. So many of the thermostatic control valves seem to ket a bit of coolant past all the time - and then on many systems a/c isn’t as effective. A manual shut off solves that problem.

ls1nova71

iTrader: (4)

Did your car have one originally? The older cars did, but not sure when they stopped using them.

Vetteman61

iTrader: (1)

Thanks for the replies. The car did originally come with one, though I don't think it ever worked since I've owned the car. I didn't realize they stopped using them. What do newer cars use?

ls1nova71

iTrader: (4)

Newer cars use blend doors to keep hot air out when not needed, but coolant always circulates through the heater core. That's why there is a lot of drama as to whether or not you should block off the heater hoses on an LS engine. I have used heater control valves that shut the water off completely on swaps for years with no I'll effects.

Vetteman61

iTrader: (1)

What kind of vehicle do you source your heater valves from?

Michael Yount

iTrader: (1)

I use a Classic Auto Air system with fully electronic heater control valve that shuts completely off when you tell it to. And I simply used two 5/8” x 5/8” x 1/8” tees between the heater hoses - that allows a small amount of coolant to always be flowing across the back side of the t’stat as GM desired.

Project GatTagO

iTrader: (7)

For some reason I had this saved in my Amazon account.


Andrew

garys 68

iTrader: (1)

If you're using the original dash controls, they were almost certainly vacuum operated. The LS engines were designed to bypass the heater core with a 4 port HCV, although I've used conventional shutoffs on both my swaps with no effects. Andrews would work well for vacuum operated.
In addition IIRC the Lincoln LS used an electronic 4 port HCV if you want to go that route.
Classic auto air also has a 2 port cable operated HCV if you need that.

Michael Yount

iTrader: (1)

Then there's this -- nice piece -- https://www.lojkits.com/products/ls-...r-bypass-block. Then put your heater control valve between the bypass and the core.

Vetteman61

iTrader: (1)

Michael, what would be the difference between using Andrews and using the unit you mentioned and then adding a valve between the core and the Nissan unit? Are you saying that the unit Andrew posted allows some to bypass into the heater core even when shut off and that adding the Nissan unit would allow no flow at all?

ls1nova71

iTrader: (4)

The one Andrew posted looks kind of like what I'm using on my truck. Mine came off an Astro van and it allows the coolant to return when closed.

Michael Yount

iTrader: (1)

I wasn’t “saying” anything at all about the unit Andrew showed - I don’t have a clue how it works or what it does. I was simply showing a way you could 1) assure you have some constant flow around the t’stat as GM designed it to work, and 2) be able to control coolant to the heater core.

Project GatTagO

iTrader: (7)

For the record, I don't know anything about that valve. I remember finding it in some searches I was doing and book marking it. I believe it is from a late model GTO, but I could be way off on that.

Andrew

pdxmotorhead

70's fords had a pure shutoff valve, same with old mopar,, gm went full flow much earlier than some, found out it helped prevent air lock in the cooling system. YMMV