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QUICK Heater Valve Question
- Thread starter 88XJSport
- Start date
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
I don't remember which is in or out, but I'm almost sure that it defaults to hot when vacuum is disconnected.
Blaine B.
NAXJA Forum User
- Location
- Northwest Indiana
Out = open
In = Closed
Lack of vacuum = open and out.
In = Closed
Lack of vacuum = open and out.
selarep
NAXJA Forum User
- Location
- Central CA
just bypass the valve.
Blaine B.
NAXJA Forum User
- Location
- Northwest Indiana
Probably not a bad idea....
However.....
By bypassing, you allow coolant to circulate through the core year round. It'll keep it cleaner and not give it time to stagnate and gunk up in there...
But however, I've heard of F350 guys adding a manual valve because after adding the valve they no longer had to use max A/C. Just because airflow is blocked off from the heatercore when you aren't using heat doesn't mean it won't still warm things up a bit.
So it's kinda debated.....
97 + there is no valve from the factory, however.
If you decide to bypass the vlave, don't forget to plug the grey vacuum line leading to the valve.
However.....
By bypassing, you allow coolant to circulate through the core year round. It'll keep it cleaner and not give it time to stagnate and gunk up in there...
But however, I've heard of F350 guys adding a manual valve because after adding the valve they no longer had to use max A/C. Just because airflow is blocked off from the heatercore when you aren't using heat doesn't mean it won't still warm things up a bit.
So it's kinda debated.....
97 + there is no valve from the factory, however.
If you decide to bypass the vlave, don't forget to plug the grey vacuum line leading to the valve.
Boatwrench
NAXJA Forum User
- Location
- Petaluma, CA
My 89 doesn't have a heater water control valve so coolant constantly flows through the core. The XJ gets hot inside, even if the vent is on as there is always air passing through the core. I am thinking next year to put a control valve in.
Blaine B.
NAXJA Forum User
- Location
- Northwest Indiana
The blend doors should stop air from flowing through it though, right?
Boatwrench
NAXJA Forum User
- Location
- Petaluma, CA
To an extent yes, but there is radiant heat from the core as there is no insulation between the core and the interior. It's like exhaust heat radiates through the floor and you'll cook if the carpet and insukation is not there.
Plus on an 89, how much of the foam seal on the blend door is still there and functioning.
Plus on an 89, how much of the foam seal on the blend door is still there and functioning.
Blaine B.
NAXJA Forum User
- Location
- Northwest Indiana
I suppose.
I don't hear any complaints from 97+ owners though (with no valve), unless the system is different in terms of how the air flows?
I don't hear any complaints from 97+ owners though (with no valve), unless the system is different in terms of how the air flows?
selarep
NAXJA Forum User
- Location
- Central CA
Is the blend door cable operated on 1996-?
The heater on my 88xj has provided very little heat the past several winters ( the cabin gets warm after awhile). I still have the control valves inline and thought about by-passing them and installing 2 new hoses directly to the heater core (per the late model xjs).
After reading thispost Im rethinking that idea as Im concerned about heat during the summer months (live in Texas).
Im wondering if perhaps the heater core is just plugged up with gunk being that a continous flow of coolant is not there most of the year and that why so little heat comes off the core when I do need heat.
If thats the case whats the best way to clean out the core? I drain, flush and replace the coolant/anti-freeze on a regular bases (20k) and usually have the heater on when Im doing that. Perhaps I need to pull the hoses and flush out the heater system directly.
Any ideas????
Burrrrrr in Texas!!!!
Lester
After reading thispost Im rethinking that idea as Im concerned about heat during the summer months (live in Texas).
Im wondering if perhaps the heater core is just plugged up with gunk being that a continous flow of coolant is not there most of the year and that why so little heat comes off the core when I do need heat.
If thats the case whats the best way to clean out the core? I drain, flush and replace the coolant/anti-freeze on a regular bases (20k) and usually have the heater on when Im doing that. Perhaps I need to pull the hoses and flush out the heater system directly.
Any ideas????
Burrrrrr in Texas!!!!
Lester
