weird heating problem...

...ok, here's a new one (and the search i've done hasn't yielded me anything similar to this particular problem):

as of saturday night, had heat. came out yesterday, and had the fan blowing ice cold when i first started the car, and warming up a little as it got to operating temp - but never warm enough to blow warm air. the air is noticeably warmer than when i first started her up, but still not hot as it should be when the heater/defroster is on...

thoughts? i plan to take it at lunch to have the heater core and radiator flushed at a local shop (wayyyyyy too cold for me to be standing outside doing it myself right now), is it possible that's the problem? if not, what else might it be?

What year? Model?

I'm working on a similar problem in my 2000 Sport. I bought her last November, and suffered through the winter with the same troubles. Figuring it needed a flush + radiator flush -or- replacement, I went through the whole system this past summer. I flushed bunches of "Old Crap & Junk" from the block & heater core, until the water ran clear while flushing from either direction.

Well, it is dang cold here in Michigan, and I'm still on very, very low heat!

(Anyway, to make a long story a little shorter)
I've traced it down to the "Blend Door" motor/actuator. It isn't opening the blend door to allow the warm air to flow through the blower "Box" inside/under/behind the dash.

Depending on the year of your XJ, you might have a motor, a cable, or (I think, but don't quote me!) a vacuum actuator working the blend door on your Jeep. Or you might even have a heater control valve on the heater hoses.
I would let your Jeep come up to heat with the hood open. Then feel both of the heater hoses. If they are both warm/hot, then you know that the coolant is making it's way all the way through your heater core, and the trouble is inside your blower box.
If the hot/warm is only noticeable on one side of the hoses, then you are not getting flow through your heater core....and the problem lies somewhere in them/heater control valve.

I hope that this helps!

Keep Us Posted.

Tall Shadow :gee:

Well, took it to the local shop at lunch...coolant flush done, still no heat. They recommended a thermostat, we'll see if that fixes anything...

new thermostat seems to have fixed the issue! (knock on wood)...i have heat again! hooray!

your t-stat was stuck open. Sorry, I didn't see it sooner.

good think it did not stick closed

I seem to be having a problem like this. I have a 1990 Cherokee. It gets up to normal temp and blows out semi-warm air. I replaced the t-stat a few months ago, so I would assume it's still good. Would a flush fix a problem like this?

XJ Fever, you have a closed cooling system. Have you burped the air out of the head? Sounds like you got Air in your heater lines.

dont think so, how would i do that?

Give this thread a whirl and it shold fex your problem. Please post a follow up letting us know how it goes.

http://www.naxja.org/forum/showthread.php?t=921185

Well to let you guys know...I have a 1990 Laredo stocked. My heating is not working to its full capability. I'll go outside in the morning, start my car up and put the heat on high. Come back out 15 minutes later and its not hot like it usually is. It is just warm, and the only hot air coming out of the vents is the defrosters. The ones on the side and head unit one are not working. What is the problem here? Please help me out! Thanks guys!

The2door said:

Well to let you guys know...I have a 1990 Laredo stocked. My heating is not working to its full capability. I'll go outside in the morning, start my car up and put the heat on high. Come back out 15 minutes later and its not hot like it usually is. It is just warm, and the only hot air coming out of the vents is the defrosters. The ones on the side and head unit one are not working. What is the problem here? Please help me out! Thanks guys!

Click to expand...

You have a vacuum leak somewhere. That will cause the incomming air to all go to the defrost vent.

Interesting...Is that vacuum leak coming from a spot behind the headlight. Because I got into a fender bender which caused some vacuum thing to crack, in which case I patched it up. But it might have came off with the cold. Does anyone know what I might be talking about. It looks like a black pill thats very large.

The2door said:

Interesting...Is that vacuum leak coming from a spot behind the headlight. Because I got into a fender bender which caused some vacuum thing to crack, in which case I patched it up. But it might have came off with the cold. Does anyone know what I might be talking about. It looks like a black pill thats very large.

Click to expand...

yes, that is the vacuum reserve and if its leaking you sometimes loose vacuum to the HVAC system. also check for broken or disconnected vacuum lines.