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  #1  
Old August 9th, 2019, 15:13
vabeachtennis vabeachtennis is offline
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Heater Control Valve

Subject: 1996 XJ 4.0



I have seen a few threads talking about capping off the vacuum line to the heater control valve. What happens if you don't cap the vacuum line off?



The new heater control valve that I bought from Autozone, doesn't seem to have a good fit to the vacuum hose, it's a little too small for a snug fit. Will this cause a problem, does anyone have any ideas on how to fix this besides just deleting it all of the way?
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Old August 9th, 2019, 16:39
lawsoncl lawsoncl is offline
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Re: Heater Control Valve

A wrap of electrical tape or some heatshrink around the nipple on the valve would snug it up a bit. I don't recall if the valve needs vacuum to bypass or to let coolant go to the heater core. If you don't connect the line from the firewall, plug it so you don't have a vacuum leak. Worse case the vacuum leak might the vents not operate properly.
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Old August 9th, 2019, 17:09
vabeachtennis vabeachtennis is offline
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Re: Heater Control Valve

Quote:
Originally Posted by lawsoncl View Post
A wrap of electrical tape or some heatshrink around the nipple on the valve would snug it up a bit. I don't recall if the valve needs vacuum to bypass or to let coolant go to the heater core. If you don't connect the line from the firewall, plug it so you don't have a vacuum leak. Worse case the vacuum leak might the vents not operate properly.
Thank you for your answer. It seems that all it needs is some tape or heat shrink. My friend was suggesting putting a zip tie on it to keep it secured. The tape sounds like the smart way to go and the zip tie may help make it secure.

I just want to fix the leak and get the Jeep back on the road. Thanks again.
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Old August 9th, 2019, 18:19
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Saudade Saudade is offline
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Re: Heater Control Valve

The heater valve defaults to "open" meaning coolant will flow to the heater core. With vacuum applied, it will bypass (closed). So leaving the vacuum line off is just like bypassing the whole thing. If you leave it off, you'll need to plug the vacuum line.

Otherwise, tape, zip tie, heat shrink tubing can all work.
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Old August 10th, 2019, 14:48
vabeachtennis vabeachtennis is offline
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Re: Heater Control Valve

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Originally Posted by Saudade View Post
The heater valve defaults to "open" meaning coolant will flow to the heater core. With vacuum applied, it will bypass (closed). So leaving the vacuum line off is just like bypassing the whole thing. If you leave it off, you'll need to plug the vacuum line.

Otherwise, tape, zip tie, heat shrink tubing can all work.
Thank you for your reply. I pushed the plastic part on the vacuum nipple (for lack of a better term) with a screwdriver ever so gently and so far it seems like a more snug fit. I will probably secure it with some electrical tape and see what happens. Thanks again.
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Old August 20th, 2019, 10:12
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four_shot four_shot is offline
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Re: Heater Control Valve

Imo a zip tie would be a better solution than tape. (No adhesive to break down.)
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Old September 7th, 2019, 16:55
vabeachtennis vabeachtennis is offline
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Re: Heater Control Valve

I put it on and it works with no modifications......so far.
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Old September 8th, 2019, 09:59
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ehall ehall is offline
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Re: Heater Control Valve

heatshrink is best
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Old September 9th, 2019, 16:06
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four_shot four_shot is offline
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Re: Heater Control Valve

Quote:
Originally Posted by ehall View Post
heatshrink is best
Potato- potaato..
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Old September 9th, 2019, 18:07
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blu3fan blu3fan is offline
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Re: Heater Control Valve

Honestly Potaato is still spelled and said wrong....
Do it right or not at all.
Here a smart easy way to fix it.
Get some hose. Cut an inch or less. rtv one end let it dry overnight. plug the port quick and easy.
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