Heater Core Parts/Tools Needed List

Firewater · Nov 10, 2013

Well, it is my turn to take on the job that all XJ owners know they must eventually face—the dreaded Heater Core replacement! The subject: ’98 Sport with AC and 160k on the ticker (surprised it took so long for the core to go). I’m not the best wrench on the block, but with the great wealth of info on here and similar sites, I feel fairly confident. Thanks . . . you guys rock!

http://www.scribd.com/doc/176480289/Jeep-XJ-Heater-Core-and-Evaporator-Replacement
Of course I will be following this, the mother of all heater core write ups. But I don’t plan on removing as much stuff. My game plan will be more like what BIGSLVRXJ wrote in this great post: http://www.naxja.org/forum/showthread.php?t=930897

Seems one of the most important things about this job is to stay organized. With that, I’ve been putting together a parts/tools needed list. Am I missing anything? Any advice or insight you gained from experience would be much appreciated. Thanks.

Parts

· Heater core

[FONT=&quot]o [/FONT]Omix-Ada: http://www.summitracing.com/parts/omx-790104?seid=srese1&gclid=CIKlyMHr17oCFdJ9OgodJnQAzw
[FONT=&quot]o [/FONT]Do you guys have any experience with this one . . . good or bad?
[FONT=&quot]o [/FONT]Cannot justify the 400+ the dealer wants for a Mopar
[FONT=&quot]o [/FONT]Will need to line with foam

· Evap core

[FONT=&quot]o [/FONT]Any decent aftermarket replacements?
[FONT=&quot]o [/FONT]AC works very well RIGHT NOW. Is it better to stick with the old stock core or roll the dice with an aftermarket unit?
[FONT=&quot]o [/FONT]If I keep the stock evap core, is there any maintenance I can do on it while I have it out?

· New ac line?

[FONT=&quot]o [/FONT]Should I anticipate needing a new one? I have heard of people having problems getting the used one back on.

· Adhesive Felt

[FONT=&quot]o [/FONT]Might as well put new felt everywhere to reduce possible creaks and squeaks

· Foam

[FONT=&quot]o [/FONT]Cross-linked polyethylene-1”: For HVAC BOX/firewall seal? Does that sound about right? http://www.foambymail.com/MC2-/cross-linked-polyethylene-foam-2lb.html
[FONT=&quot]o [/FONT]Neoprene Foam-1/8”: Blender Doors, upper heater box, insulate cores? http://www.foambymail.com/NE/neoprene-foam-sheets.html
[FONT=&quot]o [/FONT]1/8” sticky back tape from hardware store for seams and fill in
[FONT=&quot]o [/FONT]Adhesive –contact cement?
[FONT=&quot]o [/FONT]Resource: http://www.naxja.org/forum/showthread.php?t=1081921&page=2

PAG100 oil for evaporator and accumulator?

[FONT=&quot]o [/FONT] Not really sure on this. Do I need it if I use the old core? Where do you put it? Is there any oil needed for the heater core? I’m just really not understanding/visualizing this for some reason.

Tools

· Ratchet, swivel head, Metric deep sockets

· Drill

· Ratcheting box wrenches (mainly for the 13MM bolt behind the head)

· Ac disconnect (ford style)

· Electric knife for cutting foam

· Organizational stuff: zip locks, zip ties, writable tape, sharpies

Tim_MN · Nov 11, 2013

The extra supplies may come in handy, but when I replaced a 2000 XJ heater core/evap, nothing extra was required. A/C line disconnect tools are worth the cost.

Install a brand new heater core and a brand new evaporator, you really don't want to do this job again in a year or so.

Have the A/C drained and refilled by a shop, unless you have the service equipment required, this is not DIY.

lazyxj · Nov 11, 2013

To the tool list, I use a 1/4" drive set for most of the work in the dash, along with an electric screwdriver.

The PAG oil is used to replace whatever is lost from the evaporator. The oil is distributed throughout the A/C system
If you replace the evaporator, pour the oil out of it into a cup. Pour the same amount of fresh oil into the new evaporator before installing.
Check the specification tag on the A/C compressor to make sure you have the right PAG oil, it comes in different weighs.

Cottontail · Nov 11, 2013

You don't really need to remove the entire dash or remove the steering column. I would be prepared to remove the passenger side seat, for easier access.

When you are putting the case halves back together again, be certain that there is NOTHING that would cause the blend door to drag or catch. When I put mine back in, something was in the way. Manually I turned it smoothly, but the motor wasn't able to do so. The motor was strong enough to open it, but not close it. I ended up having to remove the blend door motor and buy a tiny pair of vice grips that I attached to the blend door post. I simply grab the pliers and move it forward or backwards manually based on how much heat/air I want in the cabin. It isn't an eyesore or a problem to reach, but would have caused less work if I'd have ensured it was clear of obstruction before rebuilding the heater box.

Firewater · Nov 12, 2013

Tim_MN said:
The extra supplies may come in handy, but when I replaced a 2000 XJ heater core/evap, nothing extra was required. A/C line disconnect tools are worth the cost.

Install a brand new heater core and a brand new evaporator, you really don't want to do this job again in a year or so.

Have the A/C drained and refilled by a shop, unless you have the service equipment required, this is not DIY.

Your right . . . might as well replace the evap. Are there acceptable aftermarket options or is it mopar all the way. And yes, I plan on seeing a shop for the ac drain and fill.

Thanks

Firewater · Nov 12, 2013

lazyxj said:
To the tool list, I use a 1/4" drive set for most of the work in the dash, along with an electric screwdriver.

The PAG oil is used to replace whatever is lost from the evaporator. The oil is distributed throughout the A/C system
If you replace the evaporator, pour the oil out of it into a cup. Pour the same amount of fresh oil into the new evaporator before installing.
Check the specification tag on the A/C compressor to make sure you have the right PAG oil, it comes in different weighs.

I could see how an electric screwdriver would be more easy to weild than a drill . . . i'll look into borrowing one of those.

Nice tip on the oil . . . I would not have thought of that. Makes sense how you explained it:cheers:

Firewater · Nov 12, 2013

Cottontail said:
You don't really need to remove the entire dash or remove the steering column. I would be prepared to remove the passenger side seat, for easier access.

When you are putting the case halves back together again, be certain that there is NOTHING that would cause the blend door to drag or catch. When I put mine back in, something was in the way. Manually I turned it smoothly, but the motor wasn't able to do so. The motor was strong enough to open it, but not close it. I ended up having to remove the blend door motor and buy a tiny pair of vice grips that I attached to the blend door post. I simply grab the pliers and move it forward or backwards manually based on how much heat/air I want in the cabin. It isn't an eyesore or a problem to reach, but would have caused less work if I'd have ensured it was clear of obstruction before rebuilding the heater box.

Another great tip on checking the blend door . . . will thoroughly inspect it. Besides any obstructions, are there points that can be lubed to ensure smooth function? Much appreciated.

kastein · Nov 13, 2013

I did mine in 4 hours a few weeks ago.

Tools:
steering wheel puller
Torx bit set (think I only used T25 and below, not sure. Whatever's needed to pull the switches off the steering column)
13mm sockets and crap
10mm socket, long extension, ratchet
phillips screwdriver
AC line disconnect tools!
11mm or 7/16 flex head gearwrench will make your life MUCH easier.
3/8 6 point socket, stack o extensions

You will want to have some weatherstripping or replacement foam gaskets on hand before starting. They are part number 4874 069AB from the dealer and they will want like $50, so I bought a roll of thick closed cell self adhesive foam weatherstripping from Home Depot for $8 and half ass fabricated my own instead. So far so good, no leaks yet.

Hit the pull a part for a few spare parts before you start. You want at least 3-4 of the studs that hold the HVAC box to the firewall along with the nuts that hold them on.

Tear the steering wheel off, take everything off the steering column, all the switches etc.

Take the plastic trim and metal panel off under the steering column.

Undo the (3) wiring harness connectors, the big ones. There are 2 on the left, one on the right near the TCU, they all have a big 3/8 retaining bolt in the middle. Just unscrew it until the connector pulls back.

Remove the center console. The auto trans shifter just pulls off if you put it in 1-2 (so you don't punch yourself in the face or break your windshield... don't ask) depress the button and yank hard.

Remove the bracket that holds the center of the dashboard to the trans tunnel. 4 13mm nuts and bolts, as I recall.

Loosen the 13mm bolts that hold the lower sides of the dashboard to the A pillars. They only need to be backed out about 1/2" IIRC.

Remove the right hand kick panel, the one with the fuse panel cover in it. You will need an 11mm deep socket and a phillips screwdriver.

Unplug the radio antenna cable by the fuse panel. There are a few other connectors that need to be unplugged as well, they shouldn't be hard to figure out when you start pulling the dash.

Remove the radio/HVAC controls surround from the dash. It just clips in.

Unscrew the HVAC controls from the dash and unclip the shifter cable for the blend door from the HVAC box under the dash, it's easier at that end.

Remove the top trim panel from the dash. I can't remember if you have to remove the instrument panel surround trim first or second but I'm pretty sure it has to come off first. Either way, this is another phillips screwdriver and hands ordeal, not too bad. The top trim definitely just unclips, you unclip the edge closer to you by pushing up then the edge near the windshield by pulling back and pushing up.

There is a row of 10mm nuts and bolts along the top of the dashboard frame. Remove them all.

You SHOULD be able to lift/wiggle the dashboard up and back off the vehicle now. Untangle it from around the steering column (you will need to unsnarl the wiring harnesses from around it - do this first) and set it aside. It's doable by yourself but easier with two people if anyone's sitting around wondering why you aren't paying someone else to do this stupid repair.

Now you should be looking at a giant pile of parts and the HVAC box.

Drain and disconnect the AC lines.

Disconnect the heater core lines, block off the hoses so they don't pour coolant everywhere.

Remove the 5 11mm nuts that hold the HVAC box to the dash. There are two nestled into the vacuum lines on the firewall right behind the cylinder head, two behind the accumulator/dryer roughly below the AC lines and heater core hoses, and one all the way over by the right inner fender. The studs really like to unscrew from the HVAC box instead of letting the nuts come off, so spray the threads off with brakleen, wire brush them clean, and apply WD40 before you start turning the nuts. The two behind the engine are a bastard, which is why you want that flex head gearwrench.

Now you should be able to harass the HVAC box out of the vehicle.

It has half a million 8mm self tapper screws holding the two halves together as well as a pair of small metal clips. One self tapper is hiding behind the blower relay socket, make sure you get that one. 3 self tappers hold the blower in.

Use a razor to cut all the gaskets along the separation line, then carefully split the HVAC box. It's rather brittle plastic so if it isn't coming apart somewhere, don't force it, check again for more self tapper screws.

Once it's apart, stuff the new heater core in, close it all back up, and reassemble. Reinstallation is the reverse of removal, but you curse at different points.

Make sure to screw the mounting studs (all 5 of them) back into the HVAC box fully before you reinstall. Oh, if some of them come out of the box instead of the nut coming off when you pull it apart, just stick visegrips on them and unscrew the nut, then reinstall the stud in the HVAC box while it's out. DO NOT play too roughly with the HVAC box, they are quite easy to break if you aren't gentle, especially the locating/alignment pins that keep the halves aligned and the bosses for the mounting studs.

I will be doing mine again within a few weeks probably because I discovered my AC evap core was junk when I got it apart, so I didn't put it back in. I just got the new one in the mail with my latest rockauto order, I went with the Four Seasons part on RockAuto and it looks to be a decent quality part. I can take some pics of the process then if you want.

It is really annoying to do but I didn't have to take the seats out. I started at just past 6PM after work on a Friday and had the whole dash back together by 9:38, according to the timestamps on some cellphone pics I took of the process.

Firewater · Nov 13, 2013

kastein said:
I did mine in 4 hours a few weeks ago.

Tools:
steering wheel puller
Torx bit set (think I only used T25 and below, not sure. Whatever's needed to pull the switches off the steering column)
13mm sockets and crap
10mm socket, long extension, ratchet
phillips screwdriver
AC line disconnect tools!
11mm or 7/16 flex head gearwrench will make your life MUCH easier.
3/8 6 point socket, stack o extensions

You will want to have some weatherstripping or replacement foam gaskets on hand before starting. They are part number 4874 069AB from the dealer and they will want like $50, so I bought a roll of thick closed cell self adhesive foam weatherstripping from Home Depot for $8 and half ass fabricated my own instead. So far so good, no leaks yet.

Hit the pull a part for a few spare parts before you start. You want at least 3-4 of the studs that hold the HVAC box to the firewall along with the nuts that hold them on.

Tear the steering wheel off, take everything off the steering column, all the switches etc.

Take the plastic trim and metal panel off under the steering column.

Undo the (3) wiring harness connectors, the big ones. There are 2 on the left, one on the right near the TCU, they all have a big 3/8 retaining bolt in the middle. Just unscrew it until the connector pulls back.

Remove the center console. The auto trans shifter just pulls off if you put it in 1-2 (so you don't punch yourself in the face or break your windshield... don't ask) depress the button and yank hard.

Remove the bracket that holds the center of the dashboard to the trans tunnel. 4 13mm nuts and bolts, as I recall.

Loosen the 13mm bolts that hold the lower sides of the dashboard to the A pillars. They only need to be backed out about 1/2" IIRC.

Remove the right hand kick panel, the one with the fuse panel cover in it. You will need an 11mm deep socket and a phillips screwdriver.

Unplug the radio antenna cable by the fuse panel. There are a few other connectors that need to be unplugged as well, they shouldn't be hard to figure out when you start pulling the dash.

Remove the radio/HVAC controls surround from the dash. It just clips in.

Unscrew the HVAC controls from the dash and unclip the shifter cable for the blend door from the HVAC box under the dash, it's easier at that end.

Remove the top trim panel from the dash. I can't remember if you have to remove the instrument panel surround trim first or second but I'm pretty sure it has to come off first. Either way, this is another phillips screwdriver and hands ordeal, not too bad. The top trim definitely just unclips, you unclip the edge closer to you by pushing up then the edge near the windshield by pulling back and pushing up.

There is a row of 10mm nuts and bolts along the top of the dashboard frame. Remove them all.

You SHOULD be able to lift/wiggle the dashboard up and back off the vehicle now. Untangle it from around the steering column (you will need to unsnarl the wiring harnesses from around it - do this first) and set it aside. It's doable by yourself but easier with two people if anyone's sitting around wondering why you aren't paying someone else to do this stupid repair.

Now you should be looking at a giant pile of parts and the HVAC box.

Drain and disconnect the AC lines.

Disconnect the heater core lines, block off the hoses so they don't pour coolant everywhere.

Remove the 5 11mm nuts that hold the HVAC box to the dash. There are two nestled into the vacuum lines on the firewall right behind the cylinder head, two behind the accumulator/dryer roughly below the AC lines and heater core hoses, and one all the way over by the right inner fender. The studs really like to unscrew from the HVAC box instead of letting the nuts come off, so spray the threads off with brakleen, wire brush them clean, and apply WD40 before you start turning the nuts. The two behind the engine are a bastard, which is why you want that flex head gearwrench.

Now you should be able to harass the HVAC box out of the vehicle.

It has half a million 8mm self tapper screws holding the two halves together as well as a pair of small metal clips. One self tapper is hiding behind the blower relay socket, make sure you get that one. 3 self tappers hold the blower in.

Use a razor to cut all the gaskets along the separation line, then carefully split the HVAC box. It's rather brittle plastic so if it isn't coming apart somewhere, don't force it, check again for more self tapper screws.

Once it's apart, stuff the new heater core in, close it all back up, and reassemble. Reinstallation is the reverse of removal, but you curse at different points.

Make sure to screw the mounting studs (all 5 of them) back into the HVAC box fully before you reinstall. Oh, if some of them come out of the box instead of the nut coming off when you pull it apart, just stick visegrips on them and unscrew the nut, then reinstall the stud in the HVAC box while it's out. DO NOT play too roughly with the HVAC box, they are quite easy to break if you aren't gentle, especially the locating/alignment pins that keep the halves aligned and the bosses for the mounting studs.

I will be doing mine again within a few weeks probably because I discovered my AC evap core was junk when I got it apart, so I didn't put it back in. I just got the new one in the mail with my latest rockauto order, I went with the Four Seasons part on RockAuto and it looks to be a decent quality part. I can take some pics of the process then if you want.

It is really annoying to do but I didn't have to take the seats out. I started at just past 6PM after work on a Friday and had the whole dash back together by 9:38, according to the timestamps on some cellphone pics I took of the process.

Thanks for taking the time to write this up . . . great, detailed info. I gotta pick up one of those flex head wrenches . . . I'm all about making my life much easier. In fact, my plan was to just drop the steering column on the driver's seat, remove the passenger seat, swing the dash out and secure it. I was hoping to avoid taking the steering wheel off . . . it would be just like me to bust the clock spring. But if it must come off, so be it. I gotta say you're scaring me a little bit when you say to pick up some hvac/firewall studs and bolts . . . so, its that likely they will snap:shocked: Also, I didn't realize how intricate/delicate the HVAC was gonna be.

Another good tip about avoiding a self inflicted punch to the face/ broken windshield by putting the shifter in 1-2 . . . ha,ha! You're talking to a guy who put a wrench through a toilet bowl trying to remove the seat. :roll: Yeah, this is gonna be full of idiotic moments.

I was looking at that four season evap myself. $55 vs $350+ for a mopar or ever $200 for a crown sounds like a deal. I might go that route.

Thanks again man. Looks like we'll be doing this thing at roughly the same time. Pics would be greatly appreciated. I'll take some myself . . . if for nothing else, they might be worth a few laughs:cheers:

kastein · Nov 13, 2013

It's not likely that they'll snap, but it's likely (if you live in the rust belt, or have gotten mud on the threads) that they are going to unscrew from the box instead of the nut after jamming up. Which can be fixed, but it's much nicer to have spares on hand and can just cut the old ones off. I lucked out with my brakleen+wd40 clean/lube method and all 5 came out nicely.

The clockspring is easy to not break - just leave it in place, I did. Make sure the wheel is centered when you start tearing everything apart and make sure it doesn't turn (it's not difficult to keep it from turning really, just don't mess with it) while the wheel is off and you are all set.

The HVAC box isn't all that intricate, it's just a decade old and made out of thin plastic that's been exposed to both extreme heat and extreme cold hundreds if not thousands of times. It's gonna be a bit brittle.

You might be able to do the "drop the column and pull the passenger seat" method, I've heard it works well, but I had other reasons to pull the dash on mine anyways so I just went for it, and it came out pretty easy so I'll be doing it that way again. I also like having more working space when getting the damn HVAC box off the firewall (and back on.)

The other special tool I forgot to list if you go with the method I used is a steering wheel puller. Can be rented at autozone, but it was cheap enough that I bought one years ago and have probably used it over a dozen times now, so it has definitely paid for itself.

Firewater · Feb 17, 2014

I thought I'd offer an update on this topic. First off, thanks for the help, fellas. I managed to complete the job about in late December . . . and with all the cold weather and snow we got here in the northeast, it's a good thing I did. I completed it over the course of three evenings. It took me an extra day due to the fact that the Omix Ada core was not to my liking . . . too big for box, tubes not right, etc. I was able to get a Spectra at autozone that fit well and seemed of decent quality. BTW, the Four Season Evap core was a virtual clone of the factory unit.

As I did this, I took a lot of pictures, so I thought I'd put it together in a writeup. Even though there are other good ones out there on this, it never hurts to have a different take. It is fairly detailed when it comes to the HVAC removal and might help someone. I decided it was easier for me to just start a blog and write it up on there due to the large amount of pictures used. Here's the link for anyone interested:
http://justanothersillybolg.blogspot.com/2014/02/1998-jeep-xj-heater-core-evap-core.html

Thanks again

kastein · Feb 17, 2014

Glad it worked out, sorry I never got pics for you, I haven't had the motivation to screw with it again since the heat works and the AC won't be relevant again for several more months. I'll probably fix that, oh, sometime around July at this rate :spin1:

Another thing, I really hope you put new foam rubber gaskets on the HVAC box before reinstalling it, instead of taking my advise. I tried to fake it with weatherstripping self adhesive closed cell foam and occasionally if I park at a certain angle during a rainstorm there will be water on my passenger floorboard now. Now that I make decent money again, I'll probably just nut up and buy the $60 factory foam rubber gasket set next time around... and then trace them and figure out exactly how thick/what material they used, so I can post it here and also make them myself in the future. $60 for 4 foam rubber gaskets is highway robbery.

Firewater · Feb 19, 2014

kastein said:
Glad it worked out, sorry I never got pics for you, I haven't had the motivation to screw with it again since the heat works and the AC won't be relevant again for several more months. I'll probably fix that, oh, sometime around July at this rate :spin1:

Another thing, I really hope you put new foam rubber gaskets on the HVAC box before reinstalling it, instead of taking my advise. I tried to fake it with weatherstripping self adhesive closed cell foam and occasionally if I park at a certain angle during a rainstorm there will be water on my passenger floorboard now. Now that I make decent money again, I'll probably just nut up and buy the $60 factory foam rubber gasket set next time around... and then trace them and figure out exactly how thick/what material they used, so I can post it here and also make them myself in the future. $60 for 4 foam rubber gaskets is highway robbery.

Thanks, man. I actually planned on using some minicel (or whatever its called) foam and even had some on hand, but I ended up just using what was on there and doctoring it up a bit with gasket maker. It wasn't bad and I figured it would be better than anything I could fashion. It would suck if it starts leaking. I heard they discontinued the factory foam kits . . . but I'm not sure. Maybe you can doctor your foam up from the engine bay with gasket stuff or spray foam insulation. I'd be more inclined to at least try that before pulling the box out again. I'd rather spend the time taking on other annoying projects like fixing my sagged out headliner.

Ben824 · Mar 3, 2016

kastein said:
Glad it worked out, sorry I never got pics for you, I haven't had the motivation to screw with it again since the heat works and the AC won't be relevant again for several more months. I'll probably fix that, oh, sometime around July at this rate :spin1:

Another thing, I really hope you put new foam rubber gaskets on the HVAC box before reinstalling it, instead of taking my advise. I tried to fake it with weatherstripping self adhesive closed cell foam and occasionally if I park at a certain angle during a rainstorm there will be water on my passenger floorboard now. Now that I make decent money again, I'll probably just nut up and buy the $60 factory foam rubber gasket set next time around... and then trace them and figure out exactly how thick/what material they used, so I can post it here and also make them myself in the future. $60 for 4 foam rubber gaskets is highway robbery.

Sorry to dig up an old thread but I purchased the Spectra Heater Core as well and I have since read other threads saying its not as good of a unit being that it is made of aluminum. They say it will leak and not provide adequate heat. Can you comment on your experience with it so far?

Heater Core Parts/Tools Needed List

Firewater

NAXJA Forum User

Tim_MN

Freakish Hand Strength

lazyxj

NAXJA Member #1310

Cottontail

Three-De Off-Road

Firewater

NAXJA Forum User

Firewater

NAXJA Forum User

Firewater

NAXJA Forum User

kastein

NAXJA Member

Firewater

NAXJA Forum User

kastein

NAXJA Member

Firewater

NAXJA Forum User

kastein

NAXJA Member

Firewater

NAXJA Forum User

Ben824

NAXJA Forum User

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