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heat valve?

M

maine96xj

NAXJA Forum User
Location
Maine
HEAT VALVE

i havnt had strong heat for a while in my 96 sport 4.0 aw4. i flushed heater core and no better. i took off what i think was the heat control valve and found it was a little gunked up, went to put it back in and broke a nip off it. so i just ran strait through with no valve, now i have stong heat, the valve im talking about is to the pass. side of the valve cover and is on the heater hoses just before the core... is this ok to run it without this valve?

if this is not a good idea how much would this valve cost?

also what is this valve exactly becuase it cant be the only mixing system becasue even through this valve is gone the heat still cools down some when you put the selector to cold...
 
Last edited:
With no heater valve you wont get good heat. The valve directs heated water through the heater core. I would replace the valve. Good Luck

Woody
 
valve is like a $13 part from napa or wherever. obviously a bit more at the dealer

It shuts off the flow of hot water to the heater core. If you bypass it, you won't have any heat, but if you make it pass-through, you will get some heat even when the selector is set to "cold". Not a big deal in the winter obviously, but annoying in the summer.

The reason you can still control temp is that the valve is a simple vacuum operated on/off, and the dialing in of temp with the slider control is achieved by gradually opening a cable-actuated blend door that exposes the heater core to the flow of air through the HVAC system.
 
$17.00 at Advance Auto last week.There is a metal one available for about twice that price.Broke mine last week replacing the hose from valve to T-stat housing.OE valve lasted for 240,000 and it was plastic---
Wayne
 
wow guys thanks allot i never knew there was that separate belnd door for the air. so it wont to any damage to heater or cooling system just doing a strait through with out the valve
 
langer1 said:
It only shuts the water off when you don't want heat, temperature is controlled by mixing the air.
Click to expand...
My Bad - I had that bassackwards. I was envisioning cutting the heater core out of the loop, but your right, it would be in a continious loop if just the valve was rumoved.

Woody
 
I'm running with no heater valve and it works just fine, except coolant is flowing to the heater core all the time. Some folks swear that it means you'll get heat all the time inside or that the a/c has to work harder in summer because the heater core in the dash is hot. The blend door blocks off the heater core when you select cold air anyway and I didn't notice a difference in the cool (non-ac) air in summer. Some of the later model years don't even have this valve. If you live in a really hot area, you might consider replacing it, but it's not critical.
 
thanks, i agree. i live in maine so to me being warm is a little bit more important than cooling off anyways. and plus thats what those circular turing handles on each door are for.
 
My OEM metal valve was leaking last spring so I replaced it with one from AutoZone in April....

My heat sucks though. The return hose from the heater core is hot....I must have a blend door issue :(

It operates, but perhaps one of the gaskets is worn.

Alot of newer vehicles don't have heat valves. I know some people who add manual valves in though, complaining that their AC isn't as cold as they'd like....

But the concept of no valve is that the engine stays cooler by allowing the coolant to travel a greater distance, and that the heater core won't sludge up with sitting coolant since it will always be circulating, throughout the entire year regardless of HVAC setting.
 
BTW - Anybody have a picture of their heater valve showing which hoses connect where? Can't find one on google and it would be something good to keep "just incase" someone forgot which hoses went where after removing their old heater valve.
 
HOCoolingDiagram.jpg

"Actual" picture
Picture017.jpg

Hope it helps,
Collin
 
ya good question took out my valvle like i said but my hoses are still opposite from the pic. top goes to top. and bottum to lower
 
Does it matter which way the valve sits? I didnt buy OEM hose so My hoses are not bent right. I have it hooked up but its sideways not striaght up and down. I ask bceause something still isnt right, I blew a heater hose on the way home. Taped it up added some water and made it home. So Yesterday I bought all new hoses a valve and clamps, hooked it all back up and the truck Overheats.

Thanks
 
I think I am going to Bypass the Valve for now and see if it still overheats, if it does then Ill troubleshoot from there. Maybe a thermostat or something.
 
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