cammykool

I ha e a 98 xj sport. Trying to narrow down my heat issues. It's starting to get colder in the mornings when I leave for work and I'm now resorting to driving with a blanket wrapped around me. I was told my heater core likely isn't clogged. (but I'm not sure). Something of note is the A/C is ice cold. (I replaced the compressor with a junkyard one when I bought the Jeep and charged it up). And when you change the dial to heat it has a fair bit of resistance the further you go red. And that final big click for full heat it just pops back out of if you put it to that one.

Might be unrelated but from them to time it seems to have a hard time blowing air out of the forward vents. It'll be blowing out the vents. Then stop and move to the defroster then if I turn the motor down and back up it makes a whistling sound then moved back to the vents and is fine again.

(I'm honestly most concerned with the heat)

Thanks guys as always!

EEVEE

hmm i know this is a redneck way to do it but if youre cold then invest in those plug in heaters. Jerry rigged i know but hey whatever gets us by. I need to get one as mine doesnt have heat from a bad heater core. You sound like you have a vacuum issue. Check your lines, Take the center of the dash off and take the little controller out and check the lines. Then take off your glovebox and inspect the lines as well. Thats all i can say but dont do it just yet until someone else chimes in lol. But to me it sounds like the controller is defective along with a mixture of bad vacuum lines. Does it stop blowing when you hit the gas?

cammykool

I was looking at the 12v heaters on Amazon. Reviews aren't positive. Says they are next to junk

I'll wait to start pulling parts from my dash untill we get some other folks chiming in. I'm a Cali kid. This 35° crap is too cold with no heat!

cruiser54

Jeep warmed up and engine off.

How does the upper radiator hose feel heat wise compared to the heater hoses at the firewall?

cammykool

I'm just getting off of work. What should I be feeling temp wise.

cammykool

On the hoses

EZEARL

HOT at all points cruiser mentioned. Maybe poor coolant circulation.

cammykool

Upper hose hot.
Core hoses at the firewall warmish?

Rambler65

You might want to check the blend door to see if it's stuck in the cold position.

My '99 had a similar problem last fall and reverse flushing the heater core pushed a lot of gunk out and fixed the problem.

cammykool

With the hoses not being hot?

Rambler65

As I recall, on mine the heater core inlet hose was hot and the outlet hose was cooler, indicating a flow problem. A lot of crud came out when I reverse-flushed it and I had good heat immediately afterwards. (Have not checked it yet this year since we're currently experiencing Indian Summer with 85-90 degree temperatures out here.)

If that blend door is stuck in the cold position you won't get heat even if everything else is OK. It can be checked and operated from under the dash:

https://www.cherokeeforum.com/f2/eas...3/#post3250058

cammykool

I'll try it. But neither hose was hot

cruiser54

Flush the heater core.

cammykool

Even with both lines being cold?

cruiser54

Yes. Because the coolant isn't flowing through the core.....