so as the title says, my heater blows warm, but not hot like it probably should be. which sucks since its getting cold out here in the NW, so what could be the cause of this, and whats the solution? thanks everyone

 

What temp does your XJ get to during normal operation? Should be 200-210. Also, check the hoses going into the firewall from the heater control valve...at normal temp with heat on they should both be hot. If one is noticeably cooler than the other, you may have a clogged heater core. Or the control valve itself is bad...make sure the vacuum line on the top of it is connected properly. Or hook up a power inverter and plug in a few electric griddles or a space heater

 

There is no heater control valve on a 2000 xj.

But yea, cab heat is simply a byproduct of engine heat so post up your coolant temp as per the dash gauge. 200-210 is the target.

Partially clogged heater cores are very common as well.

 

x2 on the heater core. a reverse flush will cure this.
low coolant level can also cause a no or little heat issue.
also an issue with the blend door could cause a low heat issue if its not opening all the way, does your AC operate properly?

 

I have 2 cherokees, a 98 and 99. both had lackluster heat and it is frickin cold. anyway, did the backflush, and both have HOT heat now - HOT enough that you need to turn it down after a few.

make sure you use clr as in the video, and the air compressor. you will be amazed as to what comes out. and I had flushed the radiators of both less than a week before.

the backflush is the cure.

 

Here is a link to the video illustrating the use of CLR in backflushing the heater core.

 

thanks everyone, the temp gauge reads between 200-210 all the time, and the hoses are both pretty warm. yes the AC works just fine, so i guess i will do the reverse flush and see if that helps, worst thing thatll happen is it wont work, right? so i figure its worth a shot! ill let you all know!

 

Have you had a chance to do the flush, I will be following this thread bc i'm in the same situation. Both hoses are hot and air blows warm

 

I plan to do the reverse flush but will that help the fact my gauge never goes above 125? I get luke warm heat at best.

thanks

 

NO. You must get the coolant temp up to the 200-210 range first.

Try a new thermostat (195 degree) and verify the temperature you are seeing on the gauge is correct by pointing a point and shoot infrared thermometer directly at the thermostat housing. Gotta make sure what you are seeing is correct so you aren't chasing your tail.

 

This is what I'd say. I just changed my thermostat because I hadn't had heat in years. Its a quick easy fix even for those who are mechanically challenged and solved my problem. And to think I didn't have heat for years all because of an $8 part.

 

i have not been able to do it quite yet. had some financial problems recently and havent had the money to buy coolant and CLR lol, but soon hopefully

 

I am going to take your advice and change the thermostat first, will do that today and let you know what that does. thanks

 

My 1990 XJ blew luke warm air after a thermostat change, still the same. Flushed the heater core which was really easy and cleaned the heater control valve with parts cleaner...now it is hot and working fine..

 

Do this.

I did this Saturday and my heat works GREAT! The amount of crap that came out was rediculous! Flush it about 5x both directions, put the CLR in (I did a 50/50 mix at first), flush it again, use compressed air, flush till clear, then CLR at full strength for 2-3 minutes, flush both directions, use compressed air, flush with water again, reconnect, top off and enjoy. My heat works great now.