1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

Heater core or ...

Discussion in 'Jeeps' started by AbsoluteH&L, Jan 5, 2010.

  1. AbsoluteH&L

    AbsoluteH&L Senior Member
    Messages: 573

    I just with in the last month flushed the cooling system and put in a new thermostat. But I still can't get crap for heat. Is this my heater core or do I have other issues. This is an 01 Cherokee with 77000 on it and the radiator has been replaced and is still in good condition. I worry that since I have replaced the radiator already is the heater core now shot too?
  2. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,617

    need more info, or just start replacing stuff

    Do you get air flowing out of your heater but not hot air?
    the heater works by directing air through the heater core by a flapper. If the flapper is stuck you wont get heat. does your heater controls work? Do you get air coming out at your feet, defrost...
  3. AbsoluteH&L

    AbsoluteH&L Senior Member
    Messages: 573

    Yes air will come out where ever I set it to come out, It's just not that warm.
  4. LEVE

    LEVE Member
    Messages: 79

    You can download a 2001 Jeep XJ Factory Service Manual for free:

    2001 XJ Factory Service Manual

    IIRC, it's about 42 megs.It will easily guide you through the ins/outs of that heater. IIRC, there could be vent actuation problems even if the heater core were free of sediment.
  5. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,617

    are the hoses going to the heater HOT, both going in and coming out. if both are hot you have an air obstruction. Ether debris or the temperature flapper is not working.
  6. JeepTJ

    JeepTJ Senior Member
    Messages: 225

    What temperature thermostat are you using? 190F is stock and you should not go colder (it will mess up emmisions and engine computer operation).

  7. affekonig

    affekonig Senior Member
    Messages: 909

    Just to add a bit, if one is hot and one isn't, your heater core is most likely clogged. You can flush it out pretty easily, there are even videos on youtube showing how to do it.
  8. AbsoluteH&L

    AbsoluteH&L Senior Member
    Messages: 573

    Well that will teach me! I think flushing the system is what clogged it. I took off the hoses to the heater core and could hardly get any water to flow through it. Gave it a few short hits with the air gun, VERY short (didn't want to make it all worse and start a leak) The junk that came out was nasty. I think when I flushed it originally I didn't get the reservoir clean enough and the crap got back into the system. Not great, but a lot better now! I think I still need to flush the core a few more times, but I need to wait till it's a little warmer so I can hook up the garden hose. Unluckily we are calling for single digit temps the next few days.
  9. snyps

    snyps Senior Member
    Messages: 101

    Garden hose works well.. just flush it backwards. I have also in the past diluted a little CLR in water and filled it up and let it sit.. Then back flush it.. It helped get a ton of junk out of it!
  10. AbsoluteH&L

    AbsoluteH&L Senior Member
    Messages: 573

    My garden hose would have froze. Brrr! I got a gallon jug of warm water and pored it in one hose till it came out the other. Then just blew in it to flush it, yes backwards. Did it about 4 times then put it all back together. Had the best I've had in months within minutes. Good thing to, it's going to go to get cold and snowy here this weekend!