Early XJ heater core replacement

So I have searched a crap load of places and no real write-up for the early XJ's. I have an 89 cherokee. Soooo here is my go at it.

First things first. After you remove your heater lines. Mines been bypassed for awhile till I could get to replacing the core. You need to remove the center console and lower dash panel and kick panel. The beer is optional.


Disconnect your electrical wiring and the one vac line, and heater control cable.


Remove your blower motor and remove the 3 nuts that are holding in the heater box section. (I circled them in red)


Back on the inside. There are four screws/bolts that hold the housing in. Bolt 1 and 2 are obvious. 3 is in the back. Just follow the seem that #2 is on and you will find it. There is a clip on the same bolt that has to be removed after the bolt is out. 4 is up in the dash, right above the words in the pic.


Once the bolts are out. The dash main support bolt on the right side has to be removed. Next step I have no pic of as I needed both hands to do it. You need to pull the dash out carefully and pull the heater housing back and down at the same time so the mount studs on the firewalll will come away from the dash and let it come out. This is what you will have after the housing and heater core is out.. hint-- I pulled the dash out of the way(past the support mont hole) then put the bolt back in abit, that held the dash out enough to get both hands on the housing.


Put new core in and screw it in(by the top between the two tubes)


It goes back in just like it came out. The hardest part about putting it back in was getting the studs back through the holes in the firewall. I am not going to say it was easy becouse it was a pain in the rear. But it does go back. Once up put the 4 screws back in and tighten then replace the 3 nuts that hold it to the firewall.


Replace your blower motor.


Reconnect your wiring and heater control cable, then replace your lower dash panel and center console


Then hook haeter lines back up, add coolant, and start the coolant air bleed process. I was able to do this in about 5 hours and that is with taking pics. I think my neighbors think I'm crazy. I was out doing this and didn't finish till about 1am. If you want to post this else were on the web feel free aslong as you add my name Jay Furness as the original writer. I hope that this helps some people out. Thank you

hmm.

wish that missing pic was there.

how did you get that section of the box to drop down? there are 6 bolts holding down the entire heaterbox assembly...

very nice write up, now how different if any are the newer xj's...97+?!

:thumbup:

jeepcomj said:

hmm.

wish that missing pic was there.

how did you get that section of the box to drop down? there are 6 bolts holding down the entire heaterbox assembly...

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You only need to take out the three bolts out for that section. To seperate the sections pic #4 shows the 4 screws plus clip that needs to be unscrewed. If you are going to take the whole unit out and not just that section yes there are more bolts that hold it to the firewall. As I said to get it to drop out you pull down and toward the rear of the Jeep. It will not just drop/fall down you have to wiggle it around a bit but it does come out.

blackdoutxj said:

very nice write up, now how different if any are the newer xj's...97+?!

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That to be honest with you I am not sure.

outlander said:

:thumbup:

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Yah I figured it would be good for my 12th post. Everybody has helped me out so much I just wanted to return the favor.

thanks for that!

I've go an '89 and likely will have to do the same thing, thanks for the effort to document your work for us who are amateurs at this refurbishing thing. :yelclap:

Cool deal. Glad to see this one finally covered.

Wow I wish that it was that easy for an 85!

Good write up. I don't think I would have tried it without the pictures.

I started the replacement today. I'll have to finish tomorrow. I guess I'm a little slow.

A couple of things.

I had to remove the plate that held the pressure bottle to get to the blower motor. Two of the bolts just spun because the blind nuts didn't hold so I had to pry them out. I converted to an open system years ago but had never taken the plate out.

I had working AC so I had to have the system discharged first. Then I had to detach the AC hoses which wasn't fun. You can see that Magimerlin had cut his lines in one of the pics so he didn't have to deal with that. You can also see in one of his last pics that he removed the AC core before putting things back together.

I found more screws inside than indicated. Especially one that was up high under the dash thru a metal tab that is pop riveted to the heater box. There was also a plastic strap that went around the heater box and was attached above the heater box. I had to cut the strap. Mine looks like it's never been apart before. Maybe his had been apart before and not all screws/etc were put back. I plan on skipping a few when I put it together.

I broke the same portion of the heater box that he did. I didn't even notice he had broken his until I broke mine and looked at his pics again. The plastic must be weak there. I'll have to glue it back on.

It's an Automatic so I had to disconnect the TCU which was behind the lower dash panel on the passenger side.

I had to pull the dash back farther than he seems to have needed to.

Ther were two screws holding in the heater core. One was between the two pipes as shown but there was also one at the bottom of the heater core thu a tab that was welded on. The new core had the tab also.

Lastly, it's not fun doing a heater core in January in New England in your driveway. Although it was a balmy 43 degrees today. Better than the single digits last week which was when it died.

Thanks for the good writeup with pics

Vote for sticky?

karstic said:

Thanks for the good writeup with pics

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Havent look at this post for awhile for any ?'s. Your welcome.

I know I am reviving this thread, but Merlin, do you think it is possible to do the heater core with the evaporatorin place? I have A/C and would like to keep it that way living in AZ.

I have a friend with a Snap-On A/C machine to evacuate my A/C so I can remove it if necessary, but if its not necessary, why bother...

Thanks,

nope not possible.

Yep, I looked it up in the FSM (once I figured out which section to use), and disassembled my dash, the a/c evap core is directly in the way. Thanks for the reply, though. My freon resides in my friend's tank while I go back to my three-day workweek. ...until next weekend.

Thanks again!

Thanks so much for this writeup! Its not that bad of a job to do and its worth the comfy cab when its so cold outside. I picked up a core from AutoZone & another from CarQuest as comparison, I definitely recommend spending another $15-20 for the one from CarQuest. You can tell by looking at it that its a higher quality part.

Wish I'd seen this thread before I got as far as I have. 1990 XJ and I have the console out, the dash laid back over the lowered steering column and I can't get my fat hands in a couple places... Thanks though. I see the things I was missing!!! MAYBE I can get this finished tomorrow afterall.