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Heater control Valve...

H

hayhaulerleradoxj

NAXJA Forum User
Location
Denison, Texas 75020
Is their anybody here that has found a way to bypass the heater control valve with a ball valve set up....something is really wrong with those valves now days. Every time I buy a new one its leaking before winter is over....:wave1::wave1::wave1:
 
In the later models the valve is not there. Remove it and run the late model hoses.
 
Two lengths of 5/8" heater hose will fix that. Did it on my 88 MJ ... Just made it look like my 00 XJ. Never had a problem.
 
Thanks fellow's....I'll just remove it and install new hoses...I guess Chrysler thought that device would prolong the life of the heater coil......I just got a used replacement engine from Sharper Edge Engines..and after a little work on it I'll be installing it......NAXJA....
 
The valve reduces heat in the cab when you want the heater off. Buy a better quality valve or delete it.
 
hayhaulerleradoxj said:
Thanks fellow's....I'll just remove it and install new hoses...I guess Chrysler thought that device would prolong the life of the heater coil......I just got a used replacement engine from Sharper Edge Engines..and after a little work on it I'll be installing it......NAXJA....
Click to expand...
The heater control valve was pretty typical of most manufacturers of the era. It was a problematic way to fix a problem that didn't exist and cause another problem at the same time.
They were eliminated as having coolant constantly through the heater core led to longer life of said cores. And the increase in flowing coolant capacity helped as well.
The amount of heat generated by the flow is negligible at best, and nowadays most new vehicles have a constant flow anyway. You won't notice the minute amount of radiated heat from a core with no fan pushing it out. Simply turning the heater lever to off shuts the fan down (other wise the fan runs at all times).
 
Re: Heater control Valve issues/ alternatives

I have an '89 XJ LTD w/ 4.0L I-6.
I converted the cooling the cooling system '92 & later design, (w/ reservoir).
The heater valves for this configuration are all plastic and they all leak!!!

I'm considering a couple options, but not sure if they may create other issues.
1) Using the all-metal valve for the 2.5L engines - not sure how to plumb it,
anyone done this conversion? any issues?

2) Eliminating the valve all-together
-running 3/4" engine connect to 3/4" heater core connect & 5/8" engine
connect to 5/8" heater core connect effectively reverses the heater
core coolant flow, any issues w/ that?
I don't want to install reducers if they're not necessary.
-concerned about the constant heat source in the cab, is this an issue
w/ the older, (1989) models?
 
I bought a length of both when I did my '95.

0DDBBDE6-97C9-46B5-BAF7-8EB7E547B75D_zpskzur0qei.jpg
 
Thanks for the pic.
On my '89 the heater core is different, the 3/4" outlet is the bottom one and
the 5/8" inlet is the top one.
Looks like I'll have to use the reducers after all, yuk.
 
Why, bulk 5/8" hose will stretch just fine over the 3/4" ends ... Just add a little dish soap. Both my 88 Comanche and my 00 Cherokee are plumb as such.
 
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