ctjkelley

98' SPORT 4.0 Heater gets kind of luke warm does not heat well at all. What will fix this?

Jlovekamp

First check your coolent level. if you are slightly low then you will have enough to keep from over heating but not enough to pass through the heater core and get you warm. or your thermostat could be bad, most of the time they are designed to fail open to keep your rig from over heated. try that out

RTorrez1

Most common reason for warm air and not hot is a plugged heater core. Try giving it a good flush. Also make sure to flush it in both directions. You may need to flush it both directions several times.

Toine

Did you use recently any 'stop leak' products ?
Flush it both directions many times with tap water pressure

Aljay

Seems like I have to flush mine every season .

belvedere

Does temp gauge read normal temp? If not, try a thermostat.

95xj4.0ho

Try running it and feeling ur two hoses coming from the heater core at the firewall.they shuld both b hot to the touch.if u used a stop leak product ur beter off scraping the motor cause that junk gets in everything and kills major components like water pump, radiator or heater core.no such thing as a quick fix.u get what u pay for with that junk.

ctjkelley

Thanks guys....back flushing the heater core tomorrow. Hoping the stop leak hasn't damaged to much. However the heat was not heating prior to the use of stop leak.

Unknown XJ

Try this. Its really not all that hard to flush your heater core. https://www.cherokeeforum.com/f2/hea...e-easy-155173/ If you extend your hoses coming from your core you wont have to worry about getting any major components wet. I don't even really consider this a write up or anything. Just a how to. Hope this points you in the right direction.

ctjkelley

Well the flush went great. It wasn't as dirty as I thought it would be and my heater works!! Now what should I tackle next?

RTorrez1

Glad you got her working. It really doesn't take much crud to cause it not to heat right. All it take is enough to coat the tubing so it won't let the heat pass. Again, glad you got the heat back.

95xj4.0ho

Awesum! I found that the stop leak really did a number on my engine in my zj.heat wasn't working prior to stop leak product but it def clogged it worse! Next it was overheating and choked my impeller in my water pump.id suggest flushing the whole system when possible.good luck glad you got the heater core clear

ctjkelley

I am trying to keep from doing a flush on the whole system due to a small crack in top of the plastic on the radiator close to the battery. I hope everything will hold long enough for me to replace the radiator around mid January. I also cleaned the IAC valve today its a simple but helpful thing to do.

95xj4.0ho

I see.id wait too and just keep my fingers crossed and eyes on my temp gauge! Lol I just remember my water pump choking to death out in the middle of the woods and flushing my heater core and block over and over and over and still was getting stop leak out of my zj.

ctjkelley

yeah that sucks...i know where the leak is and it is a tiny pin hole. when i did the flush on my heater core there were no signs of the stop leak, i didnt use much at all so hopefully there isnt any damage. i guess i will see what happens when i drain the radiator for replacement. were you able to get all the crap out with any major damage?