Vacuum line/heater questions
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
1996 XJ 4.0L
Firstly, should this small line be hooked up to anything? It runs from the firewall and is currently tucked by the washer fluid bottle. It has vacuum, isn't plugged either.
Next, my heater was bypassed by the PO and has been that way since I've owned it for the past year. I'm going to be replacing the heater core, blower motor and blower motor resistor in the next couple weeks hopefully because I'd like to have heat this winter. Now my question, can anybody tell me exactly what heater hoses I will need? Ideally, I'd like to do without the heater control valve. Can I just use the heater hoses from a 97-01 since they did away with the valve? Or do I need to buy it by the foot and measure and cut it?
Anything else I should consider replacing with the dash apart?
Firstly, should this small line be hooked up to anything? It runs from the firewall and is currently tucked by the washer fluid bottle. It has vacuum, isn't plugged either.
Next, my heater was bypassed by the PO and has been that way since I've owned it for the past year. I'm going to be replacing the heater core, blower motor and blower motor resistor in the next couple weeks hopefully because I'd like to have heat this winter. Now my question, can anybody tell me exactly what heater hoses I will need? Ideally, I'd like to do without the heater control valve. Can I just use the heater hoses from a 97-01 since they did away with the valve? Or do I need to buy it by the foot and measure and cut it?
Anything else I should consider replacing with the dash apart?
CF Veteran

Joined: Oct 2010
Posts: 2,150
Likes: 12
From: Ontario, Canada
Year: 1989 Laredo
Model: Cherokee
Engine: 4.0 L 6 Renix
It runs to a vacuum dashpot diaphram on the heater hose. When you go to heat the vac opens a gate valve in the heater hose, when you slide from heat to coool at the dash control, it closes the valve, reduces the hot water flow thru your heater core. If the valve is still in place on your heater hose, then plug that onto the little tube back of the valve. If the valve is removed by a PO, then stick a screw in that to stop the vac leak.
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Is it possible it's supposed to hook up to something on the heater control valve? Which mine doesn't have because the heater core is bypassed.
I'll look around more tomorrow in the daylight and see if I can find where it could possibly go to. I haven't been able to find anything yet though
I'll look around more tomorrow in the daylight and see if I can find where it could possibly go to. I haven't been able to find anything yet though
Senior Member
Joined: Aug 2010
Posts: 850
Likes: 4
From: Arcata California
Year: 1996
Model: Cherokee
Engine: 4.0
That looks like it would go on the heater control valve. Since you don't have one because the previous owner took it out, plug it for now till you replace the heater core. Then put it back on when you get the proper heater lines and a new valve.
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Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 4,440
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From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
I'll go ahead and plug it for now then.
I'm hoping to delete the heater control valve though. I don't want to deal with the leakiness of it that so many people experience. So I may just plug it and use heater hoses from the newer year XJs (can someone answer if they will work fine for an HCV delete for my year?)
I'm hoping to delete the heater control valve though. I don't want to deal with the leakiness of it that so many people experience. So I may just plug it and use heater hoses from the newer year XJs (can someone answer if they will work fine for an HCV delete for my year?)
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'll go ahead and plug it for now then.
I'm hoping to delete the heater control valve though. I don't want to deal with the leakiness of it that so many people experience. So I may just plug it and use heater hoses from the newer year XJs (can someone answer if they will work fine for an HCV delete for my year?)
I'm hoping to delete the heater control valve though. I don't want to deal with the leakiness of it that so many people experience. So I may just plug it and use heater hoses from the newer year XJs (can someone answer if they will work fine for an HCV delete for my year?)
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Ended up ordering an aluminum heater core. Waiting for all the parts from rockauto.com to get here. Will be installing next weekend so stay tuned for more questions.
Also, for those of you with a 96 and older XJ, the two heater hose part numbers to use in order to do away with the heater control valve are:
Gates 19038
Gates 19039
I didn't see that information anywhere on here so I just thought I'd throw that in
Also, for those of you with a 96 and older XJ, the two heater hose part numbers to use in order to do away with the heater control valve are:
Gates 19038
Gates 19039
I didn't see that information anywhere on here so I just thought I'd throw that in
CF Veteran
Joined: Sep 2011
Posts: 4,172
Likes: 4
From: Riviera, Texas
Year: 1998 Sport
Model: Cherokee
Engine: 4.0
Ended up ordering an aluminum heater core. Waiting for all the parts from rockauto.com to get here. Will be installing next weekend so stay tuned for more questions.
Also, for those of you with a 96 and older XJ, the two heater hose part numbers to use in order to do away with the heater control valve are:
Gates 19038
Gates 19039
I didn't see that information anywhere on here so I just thought I'd throw that in
Also, for those of you with a 96 and older XJ, the two heater hose part numbers to use in order to do away with the heater control valve are:
Gates 19038
Gates 19039
I didn't see that information anywhere on here so I just thought I'd throw that in
Good luck with your heater core change out.
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Originally Posted by jfats100
HAHA I'd rather take a running kick to the nuts then re-do the heater core
Originally Posted by RTorrez1
When I removed my heater control valve on my older XJ's I just bought some bulk hose and replace with that much cheaper and didn't have to worry about trying to get the right size without the valve.
Good luck with your heater core change out.


