Heater control valve for my Ultima

Heater control valve for my Ultima

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2001ultima

Original Poster:

234 posts

154 months

Tuesday 25th November 2014
quotequote all
All, I have been reading about the heater ports on an LS engine and there is a lot of debate as to whether the ports can be blocked off or not. The theory is that the coolant should be always flowing which passes over the thermostat. If the flow is blocked there could be issues with the thermostat working properly. Some report no issue with the ports blocked and others do. I seem to have the issue as my ports are currently blocked as to keep the heat down in the cabin. I bought a heater control valve from a 95-00 Chevy pickup truck. It is a 4 port valve, when closed works as a by-pass and the coolant will flow back to the engine and when open will flow though the cabin to the heater core. I am going to install it in the engine bay to prevent the heat from getting to the side pod (in the summer the heat radiates). The valve has 5/8 and 3/4 inch ports. I will need a longer pull cable to turn the flow on and off. The only mod is to unscrew and remove the vacuum switch and fabricate a plate to attach the cable end. Attached is a photo of the part from (AC Delco 15-5533) and a photo of a similar valve with a plate for a cable. The other item needed is a 3/4 to 5/8 hose reducer as the heater core hoses in and out are 5/8 and the LS engine out is 3/4.




F.C.

3,896 posts

207 months

Tuesday 25th November 2014
quotequote all
2001ultima said:
All, I have been reading about the heater ports on an LS engine and there is a lot of debate as to whether the ports can be blocked off or not. The theory is that the coolant should be always flowing which passes over the thermostat. If the flow is blocked there could be issues with the thermostat working properly. Some report no issue with the ports blocked and others do. I seem to have the issue as my ports are currently blocked as to keep the heat down in the cabin. I bought a heater control valve from a 95-00 Chevy pickup truck. It is a 4 port valve, when closed works as a by-pass and the coolant will flow back to the engine and when open will flow though the cabin to the heater core. I am going to install it in the engine bay to prevent the heat from getting to the side pod (in the summer the heat radiates). The valve has 5/8 and 3/4 inch ports. I will need a longer pull cable to turn the flow on and off. The only mod is to unscrew and remove the vacuum switch and fabricate a plate to attach the cable end. Attached is a photo of the part from (AC Delco 15-5533) and a photo of a similar valve with a plate for a cable. The other item needed is a 3/4 to 5/8 hose reducer as the heater core hoses in and out are 5/8 and the LS engine out is 3/4.



Replace pull push with this "Servo valve re fit kit 50507 VUA " : dump the front end knob for something a little more elegant.
I have standard "H" Bypass on my LSX and with this valve in the side pod there's no bleed past.

http://www.vintageair.com/2014catalog/Pages%20from...


2001ultima

Original Poster:

234 posts

154 months

Tuesday 25th November 2014
quotequote all
F.C., Nice setup. I saw this 4 port electronic valve as well. See page 20 of http://www.oldairproducts.com/pdf/2013_oldairprodu...

I want to stay with the old school mechanical valve. There seems to more and more nice stuff available.

mt308

438 posts

142 months

Tuesday 25th November 2014
quotequote all
I like the old school valve too, but seem to get heat in the heater even when should be off. Anyone else suffer this issue. I have had a play recently but not been out in the car since so not sure if I gave cured it. Surely a basic valve should be just as effective as an electronic one and air should not be heated at all when fully closed?

Also when aircon or heater switched on for 10 seconds or so complete internal fog! It clears but 10 seconds is quite a long time not to be able to see out!

Mark

Steve_D

13,737 posts

257 months

Tuesday 25th November 2014
quotequote all
The Factory valve has a small slit in the first stage of opening which allows fine control.
The valve must be completly closed but the movement from closed to just starting to open is very small.
When you set up the cable pull control set it so the knob is still sticking out about 4mm when the valve is closed. This means you can give the knob a good push against the valve stop to ensure it is shut.

Steve

2001ultima

Original Poster:

234 posts

154 months

Tuesday 25th November 2014
quotequote all
mt308 said:
I like the old school valve too, but seem to get heat in the heater even when should be off. Anyone else suffer this issue. I have had a play recently but not been out in the car since so not sure if I gave cured it. Surely a basic valve should be just as effective as an electronic one and air should not be heated at all when fully closed?
Mark, Do you have a bypass? without a by bypass the pressure will push the coolant through any crack. I hope with the 4 port valve that the bypass will prevent the coolant from working it's way to the heater core.

F.C.

3,896 posts

207 months

Wednesday 26th November 2014
quotequote all
mt308 said:
I like the old school valve too, but seem to get heat in the heater even when should be off. Anyone else suffer this issue.
Mark
Yes, this is how I came to fit two valves and eventually the remote electric one.
I have the "H" bypass fitted on the bulkhead.
With the old mechanical valve fitted, even on the stop the water would get passed and fight the air-conditioning.
New valve, happy days.

ETS. the electric four port valve on page 20 of the old air catalogue would have been my choice had I known of its existence, both feed and return sorted!

Edited by F.C. on Wednesday 26th November 00:26

mt308

438 posts

142 months

Wednesday 26th November 2014
quotequote all
2001ultima said:
mt308 said:
I like the old school valve too, but seem to get heat in the heater even when should be off. Anyone else suffer this issue. I have had a play recently but not been out in the car since so not sure if I gave cured it. Surely a basic valve should be just as effective as an electronic one and air should not be heated at all when fully closed?
Mark, Do you have a bypass? without a by bypass the pressure will push the coolant through any crack. I hope with the 4 port valve that the bypass will prevent the coolant from working it's way to the heater core.
Thanks, yes I do have a bypass. I have adjusted the cable recently so that there is half an inch or so behind the control knob when pushed fully shut just in case it wasn't going all the way back. Will test it again when the weather dries up a bit. If still hit will look at other solutions. My aircon is fighting hot air so it never gets really cold. Not an issue this time of year but could be better in the Summer.

Mark

mt308

438 posts

142 months

Wednesday 26th November 2014
quotequote all
Steve_D said:
The Factory valve has a small slit in the first stage of opening which allows fine control.
The valve must be completly closed but the movement from closed to just starting to open is very small.
When you set up the cable pull control set it so the knob is still sticking out about 4mm when the valve is closed. This means you can give the knob a good push against the valve stop to ensure it is shut.

Steve
Just read this after replying to later comment. Steve - I have just done what you suggest but haven't tested it yet due to horrid weather.

Do you now have no heat at all in the air if you turn the fan on with valve closed and aircon switched off?

Mark

Edited by mt308 on Wednesday 26th November 08:01

2001ultima

Original Poster:

234 posts

154 months

Monday 30th November 2015
quotequote all
Some photos of the 4 valve heater by pass install. It work out nice and keeps the cabin free of radiant heat.







Part purchased from: http://www.oldairproducts.com/pdf/flipbooks/2013_f...
Page 16.

heater hoses used from engine to valve: http://www.summitracing.com/parts/dac-70001

You will likely need a reducer for the larger heater port (engine port) to the valve (I believe 3/4 to 5/8 if I remember). I originally had AN fittings in the engine heater ports and the ports blocked which was not the right thing to do as the coolant needs to be constantly flowing past the thermostat for the thermostat to work properly.