Shut off valve for heater hose
 

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?

Re: Shut off valve for heater hose
 

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.:chevy:

Re: Shut off valve for heater hose
 

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.

Re: Shut off valve for heater hose
 

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.

Re: Shut off valve for heater hose
 

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...

Re: Shut off valve for heater hose
 

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.

http://67-72chevytrucks.com/vboard/a...1&d=1466636461

Re: Shut off valve for heater hose
 

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.

Re: Shut off valve for heater hose
 

I actually have the gen IV with servo heater valve. I agree that it stays in place once it's in position, but I don't like that the valve opens when the ignition is off. I have verified that it closes all the way, but the heater core lines inside the truck are hot to the touch while the AC is running which leads me to believe that the valve is still letting some water through.

Re: Shut off valve for heater hose
 

A gen iv servo operated shut off valve wont open when the key is turned off, they stay where they are until changed, meaning if you have it set to cold, the valve will be shut. When you turn the car off it will remain shut. If you turn the fan off, and then change it to hot, the valve will remain shut until you turn the fan back on, then the valve will open and let water flow through the heater core. All the servos work like this including the blend doors. When you shut the car off they dont default to the defrost position do they? If youre getting heat in the heater core with the heat valve shut to offf, to me sounds like a bad valve, I would contact VA and see what they say, maybe they'll srnd you a new one.

Re: Shut off valve for heater hose
 

I can try contacting them again, but I want to say that I contacted them a while back and they told me then that it was normal operation or it to open when the ignition was off.

Re: Shut off valve for heater hose
 

After looking at the electrical drawing again, it looks like the valve should have constant power and ground which to me should me that the valve would operate like you have suggested. I may have to look through the wiring again to see if something is wired incorrectly.

Re: Shut off valve for heater hose
 

VA confirmed that HCV is operating correctly which means I had to come up with a better solution. I picked up the escalade valve for $15 at the LAPS and made a simple latch to hold it closed when I don't want heat. When it is closest the heater core it creates an internal bypass so the motor never knows that the heater core has been taken out of the loop. It seems to work so far. Since I didn't really change anything other than adding this valve inline, I still have the option to remove it and replace it with a ball valve if I'm not happy with the operation.

Re: Shut off valve for heater hose
 

Latch closed

Re: Shut off valve for heater hose
 

That ought to work.

Re: Shut off valve for heater hose
 

Worked well today, but I stopped by the auto parts store to pick up a few things and a guy walked in with half of one of the valves I just installed. I asked him what happened and he said that it's the third one that has broken on him. I think I'll reconsider the ball valve idea.

Re: Shut off valve for heater hose
 

Is it a Doorman replacement? Some times Doorman plastic parts are not so good.

Re: Shut off valve for heater hose
 

Old thread, but new for me... Maybe the Vintage Air valve closes when the car is turned off so that the valve doesn't sit in one position for 8 or 9 months and get "stuck"?

Re: Shut off valve for heater hose
 

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

Re: Shut off valve for heater hose
 

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!

Re: Shut off valve for heater hose
 

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.

Re: Shut off valve for heater hose
 

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.