Can Anyone tell me what this is?

[Jkrew]

Hi everyone! I was working on my 94 2x4 and a valve gasket (?) broke. It was super rotted, so i was going to replace it. Only problem is I can't figure out what is? Can anyone help me out? It's the piece that's taped up in black.

I was hoping to go to NAPA and pick up a new one, but i need to know what it is, and my Chilton's has no diagram showing it. Any help anyone can give me in identifying and replacing it would be awesome, thanks!

 

[Blacksheep Josh]

never seen anything like that. i have a 93 and mine are just the tubes going in/out of the firewall. yours look like it was changed a little bit. trace the hose coming out the left and see where it ends up.

 

[JTX]

Are you the original owner? Maybe its somebodys way of bypassing the thermostat? Got me

 

[Jkrew]

No, 3rd owner. Just wondering if I can just re-connect directly. It just puzzles me cuz it was done for a reason, i think. Dunno. Just need to get it sealed because it leaks green fluid when I turn it on.

 

[Blee1099]

That kind of looks like the heater control valve. Is there a vacuum line connected to it?

 

[Jkrew]

That kind of looks like the heater control valve. Is there a vacuum line connected to it?

Yup. Leaks green fluid when the engine is turned on.

 

[Blee1099]

Yup. Leaks green fluid when the engine is turned on.

Then it is, simple swap. I believe the part runs about $15 at the local parts store. Takes about 5 minutes if that to replace.

 

[boggs1227]

yep heater control valve...just replaced mine 2 months ago.luck for me it went out in the drive way and not the road .easy to buy and replace but just make sure that the new part you buy ...the vac servo on the unit.....the new one i bought has the same servo but they relocated it's orienation on the unit !?!? so hooking up the plastic vac line will take a little redoing because now it's cramed right up against the foil insulation cover for the ac ...had to undo some tape and get some more line out to get it to properly go on the servo.

i got my new one at advance or auto zone ...so be carefull ....just something to watch for .

 

[Jkrew]

Sweeeet!

yep heater control valve...just replaced mine 2 months ago.luck for me it went out in the drive way and not the road .easy to buy and replace but just make sure that the new part you buy ...the vac servo on the unit.....the new one i bought has the same servo but they relocated it's orienation on the unit !?!? so hooking up the plastic vac line will take a little redoing because now it's cramed right up against the foil insulation cover for the ac ...had to undo some tape and get some more line out to get it to properly go on the servo.

i got my new one at advance or auto zone ...so be carefull ....just something to watch for .

Thanks so much for the heads up! I'll grab the new one today and give replacing it a shot. Any idea as to why this was done? Just curious! Thanks again to everyone for their assistance!!!!! U guys rock!

-J

 

[410Fortune]

the heater bypass valve just bypasses the flow of hot water through the heater core when the heater is not on

On the older Gen I trucks (like my BII) the passenger feet area would get super hot during the summer months because hot coolant is always flowing through the heater core

Well this little sucker was the fix, when you turn your temp control know to cold it closes and diverts the hot water back to the engine instead if through the heater core

they are VERY prone to leaking = geat way to sell more parts!
I added one to my 88 BII LOL but it is zip tie controlled not vacuum controlled (zip tie for summer, no zip tie for winter LOL)

 

[TexasBoy]

.....

 

[Blacksheep Josh]

the heater bypass valve just bypasses the flow of hot water through the heater core when the heater is not on

On the older Gen I trucks (like my BII) the passenger feet area would get super hot during the summer months because hot coolant is always flowing through the heater core

Well this little sucker was the fix, when you turn your temp control know to cold it closes and diverts the hot water back to the engine instead if through the heater core

they are VERY prone to leaking = geat way to sell more parts!
I added one to my 88 BII LOL but it is zip tie controlled not vacuum controlled (zip tie for summer, no zip tie for winter LOL)

so technically i could add this to my explorer? i don't have this bypass, but it gets hot during the summer like you said.

 

[410Fortune]

simple yes, just plumb it into the hoses.
If you want to take it a step further then I did you can also hook up manifold vacuum supply to it and use a vacuum switch and relay on a toggle switch from inside the cab to open/close it

that was my plan years ago, but I still use a zip tie to hold it open in the winter, no zip tie to close it in the middle of summer

 

[Maniak]

Yes you can retro fit it.

I have installed it on our '92 explorer and on a friends 88 f-150.

for a vacuum source I t'd off the "max ac" vacuum line (controls outside air vrs inside air). when on max a/c I have vacuum which now also stops the hot water from going into the heater core.

Assuming there isn't already hot water in the heater core I have noticed a 5-10 degree different in a/c temp.


~Mark