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My ACTUAL Evaporator/Heater Core Removal/Installation Thread.....

390462 Views 482 Replies 156 Participants Last post by  cyintherye
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Seeing as how this is a pretty common snag with our Jeeps, I figured I'd add to the list write-ups on how to do it. Lots of pics so sit back and read on

The first thing I did was disconnect the negative battery terminal. A) because you'll have your doors open and courtesy lights on for a LONG time and B) so your airbags don't go off when you're in the middle of removing the dash.......don't be lazy...DO THIS NOW. After that and while you're waiting for the capacitors to discharge and for your airbags to be safe, go ahead and start removing the following:

1) Both front seats (makes access to everything much easier)
2) Both lower a-pillar trim panels (or kick panels, whatever you call them)
3) The lower steering column cover/metal knee blocker



4) Remove the center bezel that covers up your stereo/heater controls/switch panel
5) Remove your headlamp knob by reaching up and pressing the release button on the inboard side of the headlamp switch. The knob should just slide out.
6) If you have tilt steering, set it to the lowest position and disconnect the rubber steering column surround.
7) Remove the instrument cluster bezel (held in by snaps and four screws)
8) Pry the rear edge of the top cover up to disengage the seven snaps.
9) Once clear, pull the entire top cover rearward and disengage the remaining four snaps.
10) Remove your shift knob (it helps if it's in 1-2, sit in the back seat, brace yourself and give it a good pull and it should come off. Don't punch yourself in the face while doing this)
11) Remove the shifter and transfer case bezels and unplug the light bulbs.
12) At this point, you can remove the two screws holding the front of the center console down. Open the console and remove the remaining two screws and the console should be able to be removed. It might take a bit of finessing to get around the parking brake handle though so be careful.
13) Pull the carpet (if you have carpet) back far enough so you can see the two lower nuts holding the panel center support bracket to the tranny tunnel.



14) Remove the two lower nuts and the two upper nuts and remove the bracket from the vehicle.
15) At this point in the FSM, it tells you to remove the steering column. From everything I've read, you don't HAVE to but I did. It was a pain and the next time I do this, I'll unbolt it from the bracket but I'll leave it in. You only need to be able to swing the dash out enough to access and remove the HVAC box from the firewall. Anyway....here's how to remove the column if you're so inclined.
16) I removed the airbag...don't know why...



17) You can pull the steering wheel off the column. I didn't because one of the holes for the puller was stripped so I left it.
18) Remove the lower shroud



19) And upper shroud



20) Unbolt the steering column coupler bolt from the intermediate shaft. You may need to turn the wheel in order to access it.
21) Disconnect all the electrical connectors associated with the steering column as well as the brake park interlock switch from the ignition cylinder. I removed the ignition cylinder as well but you may not need to. The interlock switch just clips in to the righthand side and drops away.
22) Remove the two vertical mounting nuts and the two horizontal mounting nuts from the steering column and support it as you lower it off the bracket. You can now pull the column out of the dash. Here's the dash with the column removed, the wiring harness on the left and the interlock switch and solenoid on the right



Here's a view of the mounting studs and coupler for the steering column:



23) Remove the bolts from and disconnect the two big electrical connectors under the lefthand side of the dash. The rearmost one should be the gray one and the forward one should be the white one. I had trouble with the white on and left it hooked up so I couldn't COMPLETELY remove the dash. No pics of these because I was pissed off
24) Just to the left of the tunnel and under the dash as well is another big grey electrical connector. Remove the bolt and disconnect this, as well as the small yellow airbag connector that should be around the middle of the under-dash area.
25) At this point, you can switch sides and roll down the glove box. There's two rubber stoppers and if you remove them, the glove box will rotate clear allowing you to gain access to the rear of the HVAC box.
26) On the lefthand side of the glovebox opening, you should see the white vacuum connector. Disconnect the two halves. Also, you should see a big green connector for the blower motor. Disconnect this as well.
27) Reach under the righthand side by the fuse panel and disconnect the two halves of the antenna cable.
28) You can go two different ways with this next step. I tried the by-th-book method and it didn't work so I improvised. The book says the remove the temperature control cable from the HVAC box by unscrewing the blend-air door bellcrank from the door shaft underneath the dash. I couldn't get it unscrewed so I removed the heater control panel, separated the cable from the control head and routed it clear of the dash itself so it hung clear and out of the way. You can do whatever is easiest for you.
29) Loosen the left and right dash roll-down screws about 1/4" They're located right next to each courtesy lamp so they're easy to find.
30) Remove the four bolts that secure the upper-forward edge of the dash to the firewall. There are two on the left and two on the right.
31) After the bolts are out, remove the two nuts (upper forward edge) holding the center of the dash to the firewall. The dash won't fall away with these removed as the studs are still holding it in.
32) With some help (I did it alone and it was a struggle for me) lift the dash up off the two center studs and then pull it backwards to clear the roll-down bolts. Your dash area should now (hopefully) resemble this:



At the left of the picture above, you can see one of the big gray body connectors.



At the center of the above picture, you can see the temp control cable, as well as the green blower motor connector and the vacuum connector.

With my dash swung out of the way due to that stubborn connector on the lefthand side....it's a mess but it looks worse than it actually was.



NOW, hopefully nothing was left connected and your dash should be out of the vehicle. If you forgot anything (or I forgot to mention anything) now's the time to disconnect or remove it. I found that bagging and labelling EVERYTHING (no matter how small) REALLY helped when I put everything back together. Grab a box for the parts bags and set aside a small corner for the bigger parts. The more organized you are, the easier the job will go for you because it's easy to misplace/lose things.

Anyways....on with the HVAC box. The FSM says to drain the coolant but you don't need to. Just make sure you have a small bucket or tupperware container to catch the small amount of fluid that will drain from the heater hoses as you disconnect them from the heater core.

1) MAKE SURE IF YOU HAVE REFRIGERANT THAT IT'S EVACUATED BY A PROPER SHOP. DON'T OPEN LINES AND LET IT ESCAPE....IT'S AGAINST THE LAW AND BAD FOR THE ENVIRONMENT. There I said it...
2) Using an A/C line disconnect tool (I paid $14 for my set at the parts store) disconnect the liquid line from the evaporator inlet and the accumulator from the evaporator outlet. Mine have never been done so they took about 20 minutes for both but they came out. Make sure you cover the lines somehow. I used a couple of bags with zip ties to keep crud out. The less contamination the better.

TO BE CONTINUED...
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Where were you about a year ago? :) This brings back memories of labor day last year...I had to do this TWICE last year...once on a 98 XJ and then on a 96 ZJ.

All I'll add, you don't really need to remove the seats, steering column or dash completely. I was able to easily get the box out by just dropping the column. You can pull the dash far enough away from the fire wall to get the box out.

Its always a good idea to totally clean out the box while you are in there...replace EVERYHING, and add some extra screening to your fresh air intake to keep crap from getting down there and causing future havoc with your evap core.

With the massive heat wave we have right now, I am SO happy I did these jobs last year...they are a lot of work, but in DC, I saved over $3000 doing it myself. $3000 for 2 weekends worth of work is totally worth it in my book...
First, you really saved me here. This information was invaluable in getting my heater core replaced. I just finished and am putting the dash back on. There appears to be a spare connector in the area of the radio, climate control, power center. The wires leading to it are lt blu (w/wht), red (w/wht), and black. There are no connectors like that in the area and nothing that seems to cross to the passenger side. Do you know if it's spare or do you have a wiring diagram for that area?
When replacing either or both of these, all the foam rubber seals need to be transferred over to the new part. Be careful when taking them off because I don't know of any part numbers for them.
Mine was the heater core that was leaking and destroyed the foam strip around the heater core. Can I just use some kind of weatherstripping or like the sticky back foam that is used between camper shells and truck bed rails??
I'm working on mine right now. I didn't want to remove the whole dash so I am doing what another guy did. I removed the glove box and cut the plastic around the evaporator. Then I cut the lower part of the dash in about the center where the glove box mounted. Now there is clearance to get the core out. The core hung up on the flared tubes on the engine side where the tubes go through the rubber in the firewall. I crushed the tubes with vise grips to make it easier to pull the core out. To get the new one in I am going to cut the holes a little bigger to make it easy to push them through the firewall. After that I'll just seal them with some RTV. Being a cheap way out I am going to just use foam rubber weather strip on the new core in the same places the old core had a foam seal on it. There was Styrofoam on the bottom of the old core that fell apart when it was removed. I think I will just use more foam weather strip in the bottom where the foam was.

It's still a bit of work but there is less chance of forgetting to plug a wire in. Also less chance of breaking some plastic dash parts pulling them apart. Jeep really screwed up making this thing. It wouldn't have taken much to make an access panel to get this thing out. Someone should make a cover to seal the hole after you cut the air box to remove the core. Bet they would sell a bunch of them.

I'm sure doing it the way I am doing it isn't for everyone. It's the hack job way. I just couldn't see taking the whole dash out of my jeep. It's old enough that it didn't hurt that much to take a saw to it. It also beats the $900 the shop wanted to do the job. And you know they would have found more things to replace in the A/C system to get that price up even more.
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Best write up ever! I'll be printing this one out!
im in the process of doing this right now on my 97 tJ. this write up is a better help than my alldata printout by far!!
I changed mine but now it seems like the compressor "struggles" for about 10-15 seconds before it starts running correctly. Makes a lot of noise and kinda vibrates the jeep. The low pressure line shakes like mad when it does this too. Anybody make sense of this? Is my compressor taking a dump now?
I changed mine but now it seems like the compressor "struggles" for about 10-15 seconds before it starts running correctly. Makes a lot of noise and kinda vibrates the jeep. The low pressure line shakes like mad when it does this too. Anybody make sense of this? Is my compressor taking a dump now?
Did you recharge it or have it done? Did you replace the small aluminum line from the condensor coil to the evaporator coil? It has a filter in it along with a expansion thing.
nice write-up man, thanks for taking the time
Still hoping to see some pat numbers for the foam or some working alternate methods for foam.
After reading this i will just do the heater core as well and replace the dryer.
Just completed this. Thanks for the write up and pictures.

A couple of things to note:
- used the lower heater hose to connect to thermostat housing creating a loop minus the heater core. This allowed me to continue driving without adding an elbow connector.
-I too had the sweet smell in the cabin over the cold months. I thought it was the heater core leaking a small bit. I didn't think freon had a smell. After getting the Evap core out, I smelled the styrofoam that the Evap sat in(mine was not as bad as the pictures. it had the same sweet smell. Could be a reaction of the oil and styrofoam that makes the smell.
-I used a blacklight to inspect for freon leaks. Aparently there was dye in the system. The only area that lit up was on the Evap core. All other areas were good.
-Wear safety glasses when disconnecting A/C lines. PAG100 burns the eyeballs. Yes I checked for pressure first. There was no pressure on the system yet it still shot out the accumulator.
- ACkits.com is full of usefull information.
- Replaced, EVAP core, heater core, Accumulator, liquid line w/orifice tube.
- checked the new heater core by hooking it up to the heater hoses before installing in the cabin. New Heater core from Rock Auto looked horrible, but it had no leaks.
- Lots of work, lots of money, not sure if it's really worth it....................
- Washed all the dash parts berfore reassembly. looks good and it's cool now.
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Just completed this. Thanks for the write up and pictures.

A couple of things to note:
- used the lower heater hose to connect to thermostat housing creating a loop minus the heater core. This allowed me to continue driving without adding an elbow connector.
-I too had the sweet smell in the cabin over the cold months. I thought it was the heater core leaking a small bit. I didn't think freon had a smell. After getting the Evap core out, I smelled the styrofoam that the Evap sat in(mine was not as bad as the pictures. it had the same sweet smell. Could be a reaction of the oil and styrofoam that makes the smell.
-I used a blacklight to inspect for freon leaks. Aparently there was dye in the system. The only area that lit up was on the Evap core. All other areas were good.
-Wear safety glasses when disconnecting A/C lines. PAG100 burns the eyeballs. Yes I checked for pressure first. There was no pressure on the system yet it still shot out the accumulator.
- ACkits.com is full of usefull information.
- Replaced, EVAP core, heater core, Accumulator, liquid line w/orifice tube.
- checked the new heater core by hooking it up to the heater hoses before installing in the cabin. New Heater core from Rock Auto looked horrible, but it had no leaks.
- Lots of work, lots of money, not sure if it's really worth it....................
- Washed all the dash parts berfore reassembly. looks good and it's cool now.
You are brave and bold sir. I have to tackle this in September or October and I'm looking forward to it about as much as one looks forward to a vasectomy.
I'm working on mine right now. I didn't want to remove the whole dash so I am doing what another guy did. I removed the glove box and cut the plastic around the evaporator. Then I cut the lower part of the dash in about the center where the glove box mounted. Now there is clearance to get the core out. The core hung up on the flared tubes on the engine side where the tubes go through the rubber in the firewall. I crushed the tubes with vise grips to make it easier to pull the core out. To get the new one in I am going to cut the holes a little bigger to make it easy to push them through the firewall. After that I'll just seal them with some RTV. Being a cheap way out I am going to just use foam rubber weather strip on the new core in the same places the old core had a foam seal on it. There was Styrofoam on the bottom of the old core that fell apart when it was removed. I think I will just use more foam weather strip in the bottom where the foam was.

It's still a bit of work but there is less chance of forgetting to plug a wire in. Also less chance of breaking some plastic dash parts pulling them apart. Jeep really screwed up making this thing. It wouldn't have taken much to make an access panel to get this thing out. Someone should make a cover to seal the hole after you cut the air box to remove the core. Bet they would sell a bunch of them.

I'm sure doing it the way I am doing it isn't for everyone. It's the hack job way. I just couldn't see taking the whole dash out of my jeep. It's old enough that it didn't hurt that much to take a saw to it. It also beats the $900 the shop wanted to do the job. And you know they would have found more things to replace in the A/C system to get that price up even more.
Were you able to get it done successfully? I'm looking for the easy way out here. Why? Well, yes, it get's extremely cold in Indiana in the winter, and I don't want to go thru that again, but for goodness sakes I paid $1700 for the Jeep and it's not worth the heartache and effort. My power locks don't even work, so I'm sure yanking on harnesses and other stuff will result in more fun problems.

I already hacked on the heater box to pull the blend door, I have no problem cutting more of it out if it means saving about ten hours of labor.

**Edit, looks like you did that for the evap. I'm wondering if it's not possible to do with the heater core since it's more towards the trans hump.
You are brave and bold sir. I have to tackle this in September or October and I'm looking forward to it about as much as one looks forward to a vasectomy.
Thank you, but it's not really that hard. Just take your time. Be gentle with the plastic parts as they become more brittle with age and UV light damage. Having this write up and pictures demystified the process quite a bit.

I lived most of my life in Indiana. Yes the winters are cold there so if you're going to do this job, don't wait to late.

Using the defrost turns on the A/C so that dry air is clearing the windows. I suspected something was wrong during rainy season when the defroster took forever to clear the windows (really noticeable on the door windows).
**Edit, looks like you did that for the evap. I'm wondering if it's not possible to do with the heater core since it's more towards the trans hump.
I left my dash hanging on the drivers side and totaly removed the heater box so I can't say for sure. But the heater core has long angled pipes that might hinder removing it through a hole you would cut:confused:
this is a great writeup.

Having done many years wrenching and making a living fixing everything and anything properly, I've learned this important fact:

Anything made in a factory is pretty much clearly not designed for ease of taking apart. "Reverse" assembly is painstaking labor and involves lots of possible damage to each part you take apart and put back together.

Here's what I suggest:

Go to junkyard. Bring battery powered dremel tool with bits. Surgically cut an access panel in the heater plastic box assembly until you have a proper sized access door. It would take a few bigger and bigger cuts until you have the shape and size correct. Take a photo with measurements on where those final, correct size cuts are.

At the junkyard, now hack or take out the evap core and heater core through your access panel you made. Take a few more photos. You may have to hack or trim mounting points that the cores hang off of.

Once you decide to do this on your jeep, go buy a new evap and heater core. Reading from these many threads...better replace both at the same time.

Using your access panel cut points, use your dremel to make your own access panel in your precious jeep. Remove your old parts, install new ones, and then either borrow or buy a plastic welder from Harbor Freight and "re-weld" your carefully cut plastic access panel. The plastic welder is a wonderful tool for repairing broken plastic pieces of trim that are irreplaceable. (Just do the weld on the backside of broken piece)

That should eliminate the entire dash ripout job that while perfectly doable for those with time/garage/skills... is the stopping point for many of us. By making an access panel....your jeep is driveable until you really dig deep.

I don't get to junkyards much in socal, and jeeps are hard to find....Most are still on the road!
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New Evaporator installed:



I don't think it would be easy(Im sure someone here has done it though) to cut out a slot for the heater core. There is a screw that goes through the top half of climate control plenum into the heater core bracket(near hose connectors) Screw access would be right up against the firewall. Seems to me that screw helps secure the copper pipes from vibrations. If you hack it out, it might cause the new heater core to fail sooner.
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Dont hack or cut stuff just do it the right way and take out the dash. You don't have to remove the steering column, just take the two nuts off and lower. Take off the turn indicator cause it might break when the dash is slung up and out of the way. Just did mine this weekend and got to add a kill switch and 10 gauge wire through the firewall for an amp. Didn't have to completely remove the center console either, just slide it back and pull the e-brake all the way up. I did not pretest the heater core (would have been a good idea) and it did look like crap out of the package and there was not enough room to add the foam strips on the sides, oh well. I ended up cutting my heater core hoses(they would not come the frick off) but they are still long enough to re-use, wewt saved $35 bucks there. I bought my evap from techchoiceparts.com full made-in-china cheap-skate product, hopefully it work, there ebay page has all positive reviews, probably swap it out again in a few years for one that costs more than $75, oh well.


Wut did you do this weekend?
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Dont hack or cut stuff just do it the right way and take out the dash. You don't have to remove the steering column, just take the two nuts off and lower. Take off the turn indicator cause it might break when the dash is slung up and out of the way. Just did mine this weekend and got to add a kill switch and 10 gauge wire through the firewall for an amp. Didn't have to completely remove the center console either, just slide it back and pull the e-brake all the way up. I did not pretest the heater core (would have been a good idea) and it did look like crap out of the package and there was not enough room to add the foam strips on the sides, oh well. I ended up cutting my heater core hoses(they would not come the frick off) but they are still long enough to re-use, wewt saved $35 bucks there. I bought my evap from techchoiceparts.com full made-in-china cheap-skate product, hopefully it work, there ebay page has all positive reviews, probably swap it out again in a few years for one that costs more than $75, oh well.


Wut did you do this weekend?
I appreciate your pics as I wanted to see what kind of clearances I'd get if I didn't remove the column or console:thumbsup:

When this Indiana heat dies down I'll be doing this.
Finished this process a few weeks ago with the help from this write-up and a Haynes Manual***(FSM is more thorough but more time consuming and difficult to navigate for this repair)... a couple of things.

Definitely take your front seats out….It takes 10 minutes and you will appreciate the extra room you have to maneuver around.

Since the blower only comes in contact with air, I would not seal it with any rtv or other bonding agent, less you want to deal with it if you ever have to replace either coils again.

If you have an auto transmission (I think manuals just have a release tab) there is a key release cable that runs from your shifter to your steering column, it is connected to your steering column via a tabbed harness...the purpose of this is to keep your key in the ignition while your transmission is in any position other than park. Mine was a PITA to get out. **I would recommend after you have access to all of your harnesses on the steering column, throw your key in the ignition, turn your key to start so you can move your shifter, put the car in reverse, N, or Drive, and then take the cable out of the harness, it puts tension on the cable and pulls the spring in the harness and makes taking it out much easier….and it will keep you from thrashing the tab and rest of the harness…which I did and had a nice little duct tape repair to deal with**

The biggest problem for me was taking out the steering column. I ended up pulling out the column with the linkage past the coupler bolt, clear into the engine compartment….it made it more difficult to put back in, but it worked.

I would recommend keeping all of your fasteners organized and labeled.

Put the right amount of oil in the AC components you replace....too much and you don't get the optimal cooling effect...too little and you can damage your compressor.....I asked an HVAC tech and he said a generic number is 2 oz for every component you replace. Don't take my word on it, do some research and put in the recommended volume***also if you’re AC system has been stagnant for awhile or infiltrated with ambient air, you should replace the dryer/accumulator. There is a desiccant bag that can bust and send desiccant into your line, destroying your compressor.

Replace both hoses and all the clamps to your heater core....it'll cost you $25 and you won't have to worry about whether or not your hose is going to leak at the clamp.

Make sure you tighten all of your wiring harnesses properly during assembly....One of my harnesses was not tight enough and I ended up spending another 30 minutes trouble shooting the problem.

All in all, it was more labor than technique, this write up definitely helped....take it slow the first time and after you do it once (god forbid you have to do it again, or help a friend) you could probably have the job done in half the time.
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Reassembly was a breeze did it in less than one hour. so far two days with cold AC woohoo!
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