mw6886

I'm a newbie and just bought a 1998 Cherokee Classic and have been wanting one for a long time.I was wondering how much heat it puts out.It has the 4.0 with auto trans.I am a mechanic so i know what I'm doing when i work on it.I have checked the heater control valve and it works freely and opens and closes the whole way.It runs at temp.(around 210)..so the engine gets hot.i just flushed the antifreeze out and replaced it with 50/50 mix and have been driving it for a week or so.It has a garden hose connector on the heater hose that i flushed it out with and it cycled through the heater core and came out the other hose..so I dont think there is a blockage anywhere.. i know theres no air in the lines.it blows semi warm air out but it doesnt seem to blow HOT air out ever..even on the 50 degree days with the fan on high it warms the inside just enough to take the chill of..any help would be appreciated..Thanx

99 Purple XJ

Sounds like a clogged heater core to me try flushing it out

djb383

Yep, sounds like clogged heater core. Our '98 will make u sweat, even with a 180 t-stat. U mentioned heater control valve.....thought those were factory deleted in '97?

mw6886

I'll try flushing out the heater core..Thanx...what i call the control valve is under the passengers side dash and is visible that connects to the cold/hot **** on the dash controls

Red Sled 01

I basically had the same issue, (low to know heat coming from the heater vents) though my temp was running a little warmer than 210. I thought I needed a new thermostat, since I seemed to be running above the halfway point on my temp gauge. I replaced my thermostat, and my water pump, and voila, working heat once again. HOT heat, too. Maybe something worth looking into.

djb383

The FSM does say a weak water pump can cause poor heater performance.

mw6886

I found another post about reverse flushing the heater core and using CLR and compressed air.I did this and it now blows out HOT air from the vents.I made a valve outta a plastic ball valve, screwed a 3/4 barb on one end and the air hose fitting on the other end to back flush the core.i did this both ways a couple of times.then i put the CLR in and let it set for an hour and flushed air and water through it and couldnt believe the junk that came out.after the water was finally clear i buttoned it up,topped off the coolant and after the engine got up to temp it was blowing HOT again.This did the trick..Thanx for all your help..