Heater control valve
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Junior Member
Joined: May 2018
Posts: 86
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From: Indiana
Year: 1994
Model: Cherokee (XJ)
Engine: 4.0 I6 H.O.
From what i am reading 97+ they removed the hcv.
If i were to do this to my 94 xj what would be the pros/cons?
Would it constantly heat the interior of the jeep?
Would it just run through and not heat the interior unless the blower motor is turned on?
I guess after deleting multiple questions the best question would be what exactly would happen if i were to delete the hcv in my 94 xj 4.0?
This is quite interesting to me.
Thank you all for your help in my research!
If i were to do this to my 94 xj what would be the pros/cons?
Would it constantly heat the interior of the jeep?
Would it just run through and not heat the interior unless the blower motor is turned on?
I guess after deleting multiple questions the best question would be what exactly would happen if i were to delete the hcv in my 94 xj 4.0?
This is quite interesting to me.
Thank you all for your help in my research!
Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
Hot coolant will constantly flow thru the heater core, but as long as the temp blend door is on cool or the air intake door is closed, as in heater off, you won't feel a thing.
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
There are members here who live in Arizona who have removed the HCV from their Jeeps, and have no problem with heating the interior.
The Pros:
The Cons.
So, there you have it!
IIRC the upper hose is 5/8", and the lower is 3/4". OR maybe it's the other way around, but the sizes are correct. Just buy about 5 feet of each and see which one fits which.
Remember to cap vacuum lines!
The Pros:
- One less thing to break.
- Fewer places to leak.
- Open space in your engine bay which is nice when doing things like changing spark plugs.
The Cons.
- -
- -
- -
So, there you have it!

IIRC the upper hose is 5/8", and the lower is 3/4". OR maybe it's the other way around, but the sizes are correct. Just buy about 5 feet of each and see which one fits which.
Remember to cap vacuum lines!
Thread Starter
Junior Member
Joined: May 2018
Posts: 86
Likes: 0
From: Indiana
Year: 1994
Model: Cherokee (XJ)
Engine: 4.0 I6 H.O.
Sounds great to me! Thank you all i will buy everything i need and do this saturday.
I believe the heater control valve is the cause of my coolant smells while driving. It is always sucked in by the vacuum pressure and small drops come out where the little arm moves up and down from the vacuum line. Dripping onto the side of my block heating up and stinking. Ive seen it happen and well if that doesnt cure it i know what i will do next!
I believe the heater control valve is the cause of my coolant smells while driving. It is always sucked in by the vacuum pressure and small drops come out where the little arm moves up and down from the vacuum line. Dripping onto the side of my block heating up and stinking. Ive seen it happen and well if that doesnt cure it i know what i will do next!
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Old fart with a wrench
Joined: Nov 2010
Posts: 14,398
Likes: 740
From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
You must not have a life. A real life I mean! LOL! Keep Cruiser in the back of your mind. He's the jeep guru. I'm pretty handy with WJs.
Thread Starter
Junior Member
Joined: May 2018
Posts: 86
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From: Indiana
Year: 1994
Model: Cherokee (XJ)
Engine: 4.0 I6 H.O.
Oh no not really its eat sleep take care of my son and wrench on whatever project i have for the day. worked at my step dads shop with a couple older guys who taught me everything from electrical to engine work. Suspension brakes you name it haha
they have id say 40+ years experience and helped them maintain 9 tow trucks and do some towing and recovery. My mom had some relationship issues with him which are now patched over and doing great but after everything decided its best to work elsewhere instead of with family. Some of my best friends have Jeeps we swear by them and its a daily project to be working on one of the Jeeps or Land Rovers. But i know i do not know everything so im on here daily researching. I go to the shop when i can since i can get good advice but i have had some of the best luck asking the guys on here since well you guys know specialize in the best toys in all of creation!

It makes my girlfriend mad how much money and time i spend restoring and modding my xj. But i see it as a lifelong project with millions of possibilities something when im old and die i can give to my son and his potental children. I just love the challenge and plan to have at least 5 different types of jeeps.
I believe through everything I do and with the help of this forum i will someday master Jeeps and mod them on the side for others who arent fortunate enough to have the tools time and passion to do this but want to offroad and enjoy life
Yeah sorry for typing all of this it was either type this or watch paint dry on a trailer hitch and receiver

Ok yeah thats bad i typed so much. I need a life.
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 238
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
No worries -
My wife hates my own love of 20+ year old Jeeps - to the point that I refer to my '95 as "My Mistress". No divorce papers YET.
I agree with the HCV elimination. The 97+ pre-formed hoses are a bit more $ (1's to low 10's of dollars.. so not a lot more) but literally will just hook right up and even look like they were supposed to be that way the whole time.
I eliminated the HCV on my '95 (with an engine out of a '94) and never looked back. Heat works great, A/C is cold (since the A/C repairs last year anyway..
) and I like having the coolant moving to prevent corrosion in the heater core. I've never had to pull apart a Jeep dash to replace a heater core and I have zero desire to find myself in that position.
My wife hates my own love of 20+ year old Jeeps - to the point that I refer to my '95 as "My Mistress". No divorce papers YET.

I agree with the HCV elimination. The 97+ pre-formed hoses are a bit more $ (1's to low 10's of dollars.. so not a lot more) but literally will just hook right up and even look like they were supposed to be that way the whole time.
I eliminated the HCV on my '95 (with an engine out of a '94) and never looked back. Heat works great, A/C is cold (since the A/C repairs last year anyway..
) and I like having the coolant moving to prevent corrosion in the heater core. I've never had to pull apart a Jeep dash to replace a heater core and I have zero desire to find myself in that position.
Thread Starter
Junior Member
Joined: May 2018
Posts: 86
Likes: 0
From: Indiana
Year: 1994
Model: Cherokee (XJ)
Engine: 4.0 I6 H.O.
Yes i agree on the fact the coolant is flowing i have completely gutted the interior of this xj once to swap the dash and other parts i do not look forward to that project again any time soon!
Although on days im out of cigarettes i think of that freshly lit Marlboro red that i set on the dash stupidly to run in the store just to try and grab it before the defrost vents ate it. Why did i have to pick that horrible habit back up hahaha
Although on days im out of cigarettes i think of that freshly lit Marlboro red that i set on the dash stupidly to run in the store just to try and grab it before the defrost vents ate it. Why did i have to pick that horrible habit back up hahaha
Thread Starter
Junior Member
Joined: May 2018
Posts: 86
Likes: 0
From: Indiana
Year: 1994
Model: Cherokee (XJ)
Engine: 4.0 I6 H.O.
Ok i just deleted it ran it until operating temperature shut it off ill let it cool down add coolant as needed then go for a real test drive
Like the two connections at the motor the two at the heater core are of different sizes. 3/4 and 5/8. Whether it would matter as far as function goes I'm not sure but the 3/4 hose on the 5/8 heater core connection could leak.
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