Heater Valve - need part #?

[MrJ]

My heater valve has corroded through. I can't seem to find a replacement that uses the pull wire at Autozone, etc. I don't care about using an exact replacement if someone has an updated solution. 12V switch might work better anyway.. ? Anyone have a part#/vendor? Thanks

[mayco]

Google "push pull heater core valve" and youll get several hits.

[bkahler]

This is the one you should use. It bypasses the heater core when heater control is all the way to cool.

Four Seasons 74643 Heater Control Valve

Brad

[Gregsch]

I replaced mine a year or so ago. Got it at O'riellys. As I remember the valve lever was the opposite so the cable had to be reworked. These are fun to install. Could they have put it in a more difficult location?

[bkahler]

Greg, any pictures of the install?

[MrJ]

Thanks for the info. I'm going to move mine down away from the top of the radiator.

[HiHoAgRV]

Originally Posted by bkahler

This is the one you should use. It bypasses the heater core when heater control is all the way to cool.

Four Seasons 74643 Heater Control Valve

Brad

Brad,
I'm aware of a drawback to that style valve. If you have a heavy heat load, the heater water is bypassing the radiator and going back to the block.The style that simply shuts off the flow forces all of the coolant thru the radiator.

I ran into issues in street/racecars where they ran hot because of this but admittedly this was at the extreme end of the scale.

[bkahler]

Vernon, that's an interesting side affect of using the H valve.

I wonder if in addition to the H valve add a manual shut off valve inline with the heater hose to totally shut off flow. A lot of motorhome owners already add the manual shutoff valve that is accessed from under the hood.

Thanks for the tip!

Brad

[Gregsch]

Originally Posted by bkahler

Greg, any pictures of the install?

Found these, does that help?
As I recall the hose near the Prestone tee connects to the valve right inside the firewall then there is a couple inches of hose connecting directly to the heater core.

[Gregsch]

Originally Posted by bkahler

This is the one you should use. It bypasses the heater core when heater control is all the way to cool.

Four Seasons 74643 Heater Control Valve

Brad

Brad, How does this valve work? Does it divert the water flow directly to the return hose? What would be the advantage of that? Looks like my valve stops flow to the heater core thus stopping all circulation.

[bkahler]

Greg, as the valve goes closes the H style starts diverting coolant back to the radiator instead of blocking off flow which creates a dead head in the line. Eventually all of the flow would be diverted to the block and flow to the heater core would be blocked.

This valve was a recommended field upgrade by GM for the P-30 chassis although HiHoAgRV indicated that this could also cause over heating of the engine in some high stress applications.

I'll try and find the document that GM provided and post it. It may already be posted on Airforums but I don't know when or by who.

Brad

[bkahler]

Originally Posted by Gregsch

Found these, does that help?
As I recall the hose near the Prestone tee connects to the valve right inside the firewall then there is a couple inches of hose connecting directly to the heater core.

For some reason I thought you were installing the H style of valve.

[bkahler]

Originally Posted by Gregsch

Brad, How does this valve work? Does it divert the water flow directly to the return hose? What would be the advantage of that? Looks like my valve stops flow to the heater core thus stopping all circulation.

Greg, here's a little more info on the H valve. I copied this image from this thread.


The page is also included in the Chevrolet Motorhome Chassis Service Guide.

Brad

[german6563]

Hi all
I discovered this week that my heater core is leaking, and many, is that this broken, why carpet was wet all the time.
so now I looked, and I find the right size or if I find out the extent of the tubes are different and then I'll have problems with the valve.
someone has an address where to get the original?
thanks
herman

[bkahler]

Herman, sorry to hear abut the problems with your heater.

This place Acme Air Parts is the only source I know of for heater parts for our motorhomes. They don't have everything but hopefully they will have what you need.

Brad