Jump to content

Heater control valve


Recommended Posts

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

Link to comment
Share on other sites

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

 

Actually I don't think that is true. All it does is close off when the engine is cold so the engine can get to operating temp quicker. The heater core temperature control is separate. Most of the State XJs out here have it eliminated and they run just fine. You just run heater tubing from the radiator/engine straight to the heater core. They are different sizes. 5/8" and 1/2" if I remember correctly?

Link to comment
Share on other sites

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

 

Not true, for sure with the HO 91-92 models. I eliminated the hot water valve several years ago by using the newer XJ heater hoses on my 91, as Chryco did in 96? Forget the year. If your HVAC system is functioning correctly and the HVAC door seals are intact, no heater core hot air will enter the cab. No hot air enters the cab w. the blower off, only ambient air. No hot air enters the cab w. the A/C on, only A/C cold air.

Link to comment
Share on other sites

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

 

Actually I don't think that is true. All it does is close off when the engine is cold so the engine can get to operating temp quicker. The heater core temperature control is separate. Most of the State XJs out here have it eliminated and they run just fine. You just run heater tubing from the radiator/engine straight to the heater core. They are different sizes. 5/8" and 1/2" if I remember correctly?

 

5/8" and 11/16". But you can use 5/8" on both. It's just a little tight on the 11/16" nipples.

Link to comment
Share on other sites

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

 

Not true, for sure with the HO 91-92 models. I eliminated the hot water valve several years ago by using the newer XJ heater hoses on my 91, as Chryco did in 96? Forget the year. If your HVAC system is functioning correctly and the HVAC door seals are intact, no heater core hot air will enter the cab. No hot air enters the cab w. the blower off, only ambient air. No hot air enters the cab w. the A/C on, only A/C cold air.

 

X2 - that's what I've found. When I converted my 90 XJ and the 88 MJ to open cooling I eliminated the valve. I have not noticed that there is any heat coming out my vents unless I want it to. I also believe that coolant flowing thru the core keeps the core from building up "crap". Keeps the whole system cleaner.

Link to comment
Share on other sites

I'd replace it, as without it (unless you block it off completly) you have heat going to the heater which disipates into the cab area during the Summer months even without the blower on. If you like it hot in the Summer you'll be just toasty. If you have A/C it'll be hot air coming out not cool.

 

Actually I don't think that is true. All it does is close off when the engine is cold so the engine can get to operating temp quicker. The heater core temperature control is separate. Most of the State XJs out here have it eliminated and they run just fine. You just run heater tubing from the radiator/engine straight to the heater core. They are different sizes. 5/8" and 1/2" if I remember correctly?

 

5/8" and 11/16". But you can use 5/8" on both. It's just a little tight on the 11/16" nipples.

 

So what do i use jest a peace of metal tube and put a bend in it

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...