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Heater Woes

RªMB°

RªMB°

NAXJA Forum User
Location
Yucaipa
My Heater Up Until Recently Blew Out Extremely Hot Air And Now Blows Warmish Hot Air Out. It Feels As If The Temperature Setting Is In The Middle Of Hot And Cold. When I Shut Off The Jeep And Than Shut The Blower Fan Off And Put The Thermostat To Cold I Hear The Heating Damper Close. I Never Had Or Heard This Before. Can A Bad IAC (Its Goin Out) Cause This Problem?

Its A '87 XJ.
 
RªMB° said:
My Heater Up Until Recently Blew Out Extremely Hot Air And Now Blows Warmish Hot Air Out. It Feels As If The Temperature Setting Is In The Middle Of Hot And Cold. When I Shut Off The Jeep And Than Shut The Blower Fan Off And Put The Thermostat To Cold I Hear The Heating Damper Close. I Never Had Or Heard This Before. Can A Bad IAC (Its Goin Out) Cause This Problem?

Its A '87 XJ.
Click to expand...

Bad IAC? No. Bad heater control valve? Possibly. Fortunately, it can simply be deleted without incident, and just tie the hoses together with a straight coupler. Your A/C won't get as cold, but your heater core will always get hot coolant at full flow.

And, please put down the SHIFT key and back away. Reading "camel case" posts gets tiressome, outside of writing programmes. Please. Typing normally will make your posts much easier to read, believe me!
 
I'm gonna track this dude down and rip the GD shift keys off his keyboard...
 
Thermostat works just fine and my jeeps temp gets up too the temp tick below 210° I do believe that it is 182°. It stays there unless in traffic or heavy wheeleing, because of the crappy dual electric fan in my XJ and needs to be upgraded to stronger ones.
 
RªMB° said:
Thermostat works just fine and my jeeps temp gets up too the temp tick below 210° I do believe that it is 182°. It stays there unless in traffic or heavy wheeleing, because of the crappy dual electric fan in my XJ and needs to be upgraded to stronger ones.
Click to expand...

THANK YOU! That is much easier to read than your regular offering - and it helps!

I still vote for checking your heater control valve. Not only is it possible for the thing to stick open or stick shut, it can stick partially open - which allows a reduced coolant flow through the heater core.

Granted, that's if the drop in heat was sudden. If not, when was the last time you flushed the system. Did you have the heater full on while you did the flush? That would therefore flush out the heater core as well...
 
I flushed the system a 2 months ago and had full heat afterwards. Is it possible if the heater control valve gets stuck that it can cause overheating problems?
 
RªMB° said:
I flushed the system a 2 months ago and had full heat afterwards. Is it possible if the heater control valve gets stuck that it can cause overheating problems?
Click to expand...

I suppose it's possible - but I'd consider it unlikely. If the heater control valve is closed, that just means that coolant isn't flowing through the heater core to heat up the air passing over it. The only time it might have some impact on cooling the engine is if you're already overheating, and you want to use the heater to help cool the engine (and old trick, that usually helps.)
 
i would say its the vacuum actuated door that controls the selection between hot and cold air, they go out every once in awhile and cause exactly what you are describing, heat in the AC and cold in the heat.
 
My sister is having the same problem with her 1997 XJ Sport. It will blow cold when turned to cold but when turned all the way to hot, it only ends up warm. The engine reaches and holds operating temperature well.

The control valve sounds like the likely culprit. Where is it located at?
 
jachristner said:
My sister is having the same problem with her 1997 XJ Sport. It will blow cold when turned to cold but when turned all the way to hot, it only ends up warm. The engine reaches and holds operating temperature well.

The control valve sounds like the likely culprit. Where is it located at?
Click to expand...

No control valve in the '97. Flush that heater core!!!! :yelclap:
 
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