Underheating
Thread Starter
CF Veteran
Joined: Sep 2010
Posts: 1,992
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From: West Bloomfield,MI
Year: 1996
Model: Cherokee
Engine: 4.0L, CAI, Edelbrock Breather, Optima Yellowtop
Even a coolant evac machine my not get all the guck out of the heater core. (There a decent machine, but you can do just as good a job without one). Look up heater core backflushing in the search. Ill bet you find a good write up. Most of the ineffective heat complaints for XJ`s are clogged heater cores.
Its cold as hell and I don't want to flush it but ya gotta do what ya gotta do. I'll do the procedure as a last resort after running diagnostics on all other cooling components. Thank you for the help man
Thread Starter
CF Veteran
Joined: Sep 2010
Posts: 1,992
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From: West Bloomfield,MI
Year: 1996
Model: Cherokee
Engine: 4.0L, CAI, Edelbrock Breather, Optima Yellowtop
It's the cold and the excellent XJ cooling systems. I drove from Central NY to Southern PA today and it didn't reach operating temp til I got where it's 30 degrees. Also, check the vacuum line on the mixer (by the dip stick). If that isn't on, or leaks, the doors in the heater won't open right and it won't blow hot air.
To get the air bubbles out, start it cold without the radiator cap on and with the heat on high, wait til it opens the thermostat and fill. Do this once a day for 2 or 3 days and there will be no more air bubbles
To get the air bubbles out, start it cold without the radiator cap on and with the heat on high, wait til it opens the thermostat and fill. Do this once a day for 2 or 3 days and there will be no more air bubbles
I bet the vacuum line on the mixer is my problem!
I burped the system and took a 15 mile drive hoping to get the Jeep up to operating temp.
On the way home I noticed the second slider on the climate control was really sticky(it's the one that adjusts how hot or cold you want your Heater or A/C to be). I had to push on it pretty hard to get the slider to move back and forth.
I'm going to go out in the garage and take a look.
Thread Starter
CF Veteran
Joined: Sep 2010
Posts: 1,992
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From: West Bloomfield,MI
Year: 1996
Model: Cherokee
Engine: 4.0L, CAI, Edelbrock Breather, Optima Yellowtop
Thread Starter
CF Veteran
Joined: Sep 2010
Posts: 1,992
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From: West Bloomfield,MI
Year: 1996
Model: Cherokee
Engine: 4.0L, CAI, Edelbrock Breather, Optima Yellowtop
Fixed the problem today.
-Bought a new Heater Control valve at Autozone for $17.99
-Bought 2 gallons of Antifreeze and a bottle of stop leak for $20ish
-Flushed my heater core out
-Took off the heater hoses and flushed those out
-Clamped everything up and attached the vacuum hose
-Burped the cooling system twice
-Filled the resivour tank
and the heat is back to normal
thank god!
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Joined: Dec 2010
Posts: 283
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From: Davison, MI
Year: 1988
Model: Cherokee
Engine: 4.0
Thread Starter
CF Veteran
Joined: Sep 2010
Posts: 1,992
Likes: 0
From: West Bloomfield,MI
Year: 1996
Model: Cherokee
Engine: 4.0L, CAI, Edelbrock Breather, Optima Yellowtop
If anything happens after this (hopefully not soon *knock on wood)
I'll probably just bypass that thing and run the hoses directly to the heater core so hot coolant constantly runs through it.