heater control valve leaking when heater is on
CF Veteran




Joined: Aug 2019
Posts: 1,601
Likes: 226
From: East Tennessee
Year: 1996
Model: Cherokee (XJ)
Engine: 242 cui
Definitely eliminate it. I can take pics from my 95 if you want them.
The cheaper option is to use "by the foot" heater hose, but the easier option is to use the 97+ hoses. They are a direct fit and I can say without exaggeration that it literally looks like they were factory.
I used a small screw and some silicone in the vacuum line and then zip tied it off to the side on some wiring channels and it's been great for me for the last 2 years.
The cheaper option is to use "by the foot" heater hose, but the easier option is to use the 97+ hoses. They are a direct fit and I can say without exaggeration that it literally looks like they were factory.
I used a small screw and some silicone in the vacuum line and then zip tied it off to the side on some wiring channels and it's been great for me for the last 2 years.
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
You can see, bottom hose (Part number 19038) from core goes to water pump, top hose from core (Part number 19039) goes to t-stat housing. Hoses are just the listed parts for any 97+ XJ. I bought these rather than "by the foot" since the I.D.'s differ on each end of the hose and I a proper fit was worth $10-15 to me.
Simple, easy upgrade. Mine wasn't leaking, but the idea of stagnant coolant eating away at my (probably OEM) core all summer was enough to convince me to do the upgrade. So far it's been perfect.
Tips for the install:
- I had issues getting the old hoses off the core and was concerned with trying to pull or force it since AFAIK the core is original, so I very carefully cut the rubber with a new razor blade. It took longer than it might have, but I was willing to take the extra time to ensure I didn't booger up the core.
- If you've got both hoses off the core, now's a great time to do a low pressure flush backwards and forwards on it.
Otherwise it was super easy - I highly recommend it for anyone who still has the HCV.
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Definitely eliminate it. I can take pics from my 95 if you want them.
The cheaper option is to use "by the foot" heater hose, but the easier option is to use the 97+ hoses. They are a direct fit and I can say without exaggeration that it literally looks like they were factory.
I used a small screw and some silicone in the vacuum line and then zip tied it off to the side on some wiring channels and it's been great for me for the last 2 years.
The cheaper option is to use "by the foot" heater hose, but the easier option is to use the 97+ hoses. They are a direct fit and I can say without exaggeration that it literally looks like they were factory.
I used a small screw and some silicone in the vacuum line and then zip tied it off to the side on some wiring channels and it's been great for me for the last 2 years.
This.
There is no reason to mess with that stupid heater valve. They eliminated them for good reasons.
I just used heater hose. One is 3/4" and one is 5/8". I don't remember which is which, but it will be obvious when you get in there. Just pick up 5' of each and cut to fit. Problem solved.
CF Veteran




Joined: Aug 2019
Posts: 1,601
Likes: 226
From: East Tennessee
Year: 1996
Model: Cherokee (XJ)
Engine: 242 cui
You can see, bottom hose (Part number 19038) from core goes to water pump, top hose from core (Part number 19039) goes to t-stat housing. Hoses are just the listed parts for any 97+ XJ. I bought these rather than "by the foot" since the I.D.'s differ on each end of the hose and I a proper fit was worth $10-15 to me.
Simple, easy upgrade. Mine wasn't leaking, but the idea of stagnant coolant eating away at my (probably OEM) core all summer was enough to convince me to do the upgrade. So far it's been perfect.
Tips for the install:
- I had issues getting the old hoses off the core and was concerned with trying to pull or force it since AFAIK the core is original, so I very carefully cut the rubber with a new razor blade. It took longer than it might have, but I was willing to take the extra time to ensure I didn't booger up the core.
- If you've got both hoses off the core, now's a great time to do a low pressure flush backwards and forwards on it.
Otherwise it was super easy - I highly recommend it for anyone who still has the HCV.
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
As fb97xj1 said, absolutely not. I did the elimination over 2 years ago when I first got my 95, at the end of last summer I fixed the A/C and I get nice cold A/C in the summer and nice warm heat in the winter. Also, bear in mind that the FACTORY setup for 97+ is what you're recreating on a pre 97 XJ with the elimination.
It's always possible that the seal on the blend door could rot away and you'd get a bit of heat leaking through, but my XJ is 24 years old with presumably the original HVAC setup and has over 320k miles on the body and get zero heat leaking when the slider is on "cold".
It's always possible that the seal on the blend door could rot away and you'd get a bit of heat leaking through, but my XJ is 24 years old with presumably the original HVAC setup and has over 320k miles on the body and get zero heat leaking when the slider is on "cold".
Junior Member
Joined: Jul 2019
Posts: 74
Likes: 15
From: Northern CO
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0
Any idea what sort of things happen by NOT having that vacuum line not plugged? I've been running it that way for 4 months.
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
I removed my HCV on my 96 as well but I didn't plug up that little vacuum hose. The other day I was wondering what the heck it was so now I know and I'll plug it up. Jeep seems to be running fine so not sure if it will run even better with this hose plugged.
Any idea what sort of things happen by NOT having that vacuum line not plugged? I've been running it that way for 4 months.
Any idea what sort of things happen by NOT having that vacuum line not plugged? I've been running it that way for 4 months.

You may find the HVAC setting (where the air output is routed) will be more responsive if nothing else.
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Senior Member





Joined: Oct 2019
Posts: 789
Likes: 234
From: Current XJ is
Year: 95
Model: Cherokee (XJ)
Engine: 4.0
Thread Starter
Member
Joined: Jun 2010
Posts: 235
Likes: 9
From: Bloodymore Murderland I am a Preacher of the Good news of JESUS CHRIST ,a Bad Actor ,Metal Bass play
Year: 1997
Model: Grand Cherokee (ZJ)
Engine: 4.0
I found some Copper pipe and used that. It works good for now
CF Veteran




Joined: Aug 2019
Posts: 1,601
Likes: 226
From: East Tennessee
Year: 1996
Model: Cherokee (XJ)
Engine: 242 cui
You can see, bottom hose (Part number 19038) from core goes to water pump, top hose from core (Part number 19039) goes to t-stat housing. Hoses are just the listed parts for any 97+ XJ. I bought these rather than "by the foot" since the I.D.'s differ on each end of the hose and I a proper fit was worth $10-15 to me.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I removed my HCV on my 96 as well but I didn't plug up that little vacuum hose. The other day I was wondering what the heck it was so now I know and I'll plug it up. Jeep seems to be running fine so not sure if it will run even better with this hose plugged.
Any idea what sort of things happen by NOT having that vacuum line not plugged? I've been running it that way for 4 months.
Any idea what sort of things happen by NOT having that vacuum line not plugged? I've been running it that way for 4 months.
this. At the 4.5 month point.


