Shut off valve for heater hose

[clemsonteg]

I have a vintage air setup in my truck along with my LS swap. The vintage air kit has a 'coolant shut off valve' which appears to be totally useless most of the time. It's electric and when the truck isn't running the valve opens when the ignition is off and is potentially allowing coolant to still flow through which is affecting the performance of the AC. I was considering adding a manual ball valve into the the return line to prevent any flow that may get past the vintage air valve. I also considered a "bypass" type valve like those that came on earlier escalades and tahoes http://www.rockauto.com/en/moreinfo....nid=394&jpid=1. My thought would be to remove or disable the vacuum pot and manually move the arm into the desired position. This would allow coolant to still flow as if the heater core were in the loop. Any thoughts or advantages to one system over the other?

[Andy4639]

Originally Posted by clemsonteg

I have a vintage air setup in my truck along with my LS swap. The vintage air kit has a 'coolant shut off valve' which appears to be totally useless most of the time. It's electric and when the truck isn't running the valve opens when the ignition is off and is potentially allowing coolant to still flow through which is affecting the performance of the AC. I was considering adding a manual ball valve into the the return line to prevent any flow that may get past the vintage air valve. I also considered a "bypass" type valve like those that came on earlier escalades and tahoes http://www.rockauto.com/en/moreinfo....nid=394&jpid=1. My thought would be to remove or disable the vacuum pot and manually move the arm into the desired position. This would allow coolant to still flow as if the heater core were in the loop. Any thoughts or advantages to one system over the other?

I have a manual shut off in mine. It works fine. One valve is all you need in the system. If you stop the flow then there is no hot water coming through the heater core to heat up the cab.

[ls1nova71]

Originally Posted by clemsonteg

I have a vintage air setup in my truck along with my LS swap. The vintage air kit has a 'coolant shut off valve' which appears to be totally useless most of the time. It's electric and when the truck isn't running the valve opens when the ignition is off and is potentially allowing coolant to still flow through which is affecting the performance of the AC. I was considering adding a manual ball valve into the the return line to prevent any flow that may get past the vintage air valve. I also considered a "bypass" type valve like those that came on earlier escalades and tahoes http://www.rockauto.com/en/moreinfo....nid=394&jpid=1. My thought would be to remove or disable the vacuum pot and manually move the arm into the desired position. This would allow coolant to still flow as if the heater core were in the loop. Any thoughts or advantages to one system over the other?

Why do you care if it opens when the truck isnt running? When you start the truck it will shut off again, so it shouldn't affect the performance of the A/C. That's how the factory ones were too, only they were all vacuum operated.

[clemsonteg]

Originally Posted by ls1nova71

Why do you care if it opens when the truck isnt running? When you start the truck it will shut off again, so it shouldn't affect the performance of the A/C. That's how the factory ones were too, only they were all vacuum operated.

The valve is servo controlled and it's slow to close. When I drive the truck somewhere and stop for a short period of time the heater core will fill with hot water on startup. Due to the design of the air box, a hot heater core has to be cooled down for the AC to start blowing cold. I have never been a fan of the valve as it is, I think it should be designed to be normally closed not normally open. I also suspect that it may be allowing some water through. I have a 16lb radiator cap, so maybe the extra pressure is forcing water past the valve.

What I am not sure of is how the LS engine should operate. I read a few threads that suggested creating a bypass rather that completely blocking the heater hoses.

[mongocanfly]

I don't know for sure but they told me when I set mine up not to plug the heater hoses which is the same thing manually valving off flow will do..they said it needs the flow thru the heater hoses for the thermastat to see hot water so it will function..didnt matter cause ive got a heater but they said if I wasn't running a heater core to just loop a hose across the fittings.that would be the same as a heater bypass valve..I do know there was a member here not long ago that was having overheating problems and he had his hoses plugged with bolts and clamps..when he looped the hose it fixed his problem.that may be why your valve is slow to close is to let enough hot water get to the thermo so it will open..once hot flow is established it can be closed off....I'm just assuming here...

[Andy4639]

I have my vacuum valve and manual valve in the same line. I have no over heating problems at all. This past week on the 2016 HRPT I drove just a tad over 3000 miles in 7 days. 1200 of those miles where in one straight long run home in 26 hrs on the road.

Temp reading straight off the ECU at speed. AC on ...no fans on.

[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.

[lowrodderchev]

Bringing it back I'm having same issue. Valve is closed but lines still getting hot anyone else with same issues

[rodstored-72]

I am looking for some similar info. I need to connect the V.A. heater hoses to me '13 Gen iv 4.8Ls. I am trying to remember which hose connects to which engine hose outlet? which hose outlet does the V.A. hose with the HCV go to? I believe the outlets are different sizes?
I am under the impression that which outlet the V.A. HCV hose is connected to matters?
thanks!

[1971Stepside]

My VA is doing this same thing. It blows cold until the engine heats up and then hot water makes its way to the heater core. VA told me that I may have the valve in backwards, but I checked and it isn't. I have the old style VA evap unit where it is still cable driven. Following this thread to see what others have done. Ironically, it is has just been too hot to get out and mess with it.

[1971Stepside]

Update: My issue turned out to be wiring. Diagram on VA showed switch upside down to what mine was and I wasn't careful enough to verify it the first time.