How To: Heater core replacement

[jeeptorino68]

First of all, the info i am providing is from my experience with a 2002 KJ (US model) your results may vary...
i split this project up into two parts, the first tearing down the dash and stuff in the way under the hood. the second removing/installing the heater core, and re-assembling. this was accomplished in 3-5 hour work sessions, it is nice to have a helper but i did it all on my own.
*WARNING* use caution when working on/around airbags, do so at your own risk, if you are not comfortable around them or are not sure they will be properly disabled, do not attempt.

Also if you choose to discharge your air conditioning system for this, do it in the appropriate manner. it is illegal to discharge the Freon into the atmosphere, take it to the proper mechanic for this, or rent the tools to do it.

Second, i have to give partial credit to Joejeeper420, he had some info that gave me the confidence to get started

from Joejeepers420's thread on LOST:
"I started by disconnecting the battery then removing the center console, then comes the A pillar handles; and everything screwed/clipped into the dash... All of the trim around the steering wheel, the column switch, gauge cluster, as well as both kick panels come out... Then the stereo and all HVAC controls. then the passenger side airbag came out. once that is done you can remove the swing bolts that are located behind the kick panels, then i took out the center mounting bolts as well as the plate. I then unscrewed the fuse/junction box at this point, then disconnected the wire harness starting at the brake switch and working my way over I fished most of it through the opening for the steering wheel. Then I disconnected the vacuum line and electrical connectors on the passenger side that go to the blower motor and the resistor, etc and fished them out a bit. After that its the main bolts that go into the firewall... I never dropped the steering column... I only loosened the two 13mm? Bolts that go up and through the bottom of the mid column up, they protrude just enough that you can't pull the dash towards you without backing them off till the ends are flush. Then there are
Two 10mm washer nuts on the bottom of the heater Box... And that just about finishes off the work in the cabin.

Then ON to the engine bay! You have to move the coolant overflow out of the way to get to the one remaining washer bolt on the firewall and the input output hoses On the heater core... Evacuate the AC then disconnect evaporator... Back in the cabin you can pull the dash back enough to wiggle the old heater box out. Twist it back towards you so the heater core openings face up and pull it out.

Jump around for joy at this point and look at your car in disbelief but be full of confidence because its not rocket science

When re installing take care to be easy and not Force it in... You can make enough space to get it in without forcing it. Also take care when handling your fuse/junction box... When I buttoned everything back up my gauge cluster was dead... I had to reseat the connectors and reset the battery... After that everything should be gravy. Enjoy the heat!"

Third - thanks goes to Diggerfreek on LOST for info on taking out the center console, dash, and passenger side airbag/dash - NOTE those write ups were for a KK but very similar to a KJ

i will add to this, and pictures i took.
reference the following threads/links:
1) Link to Joejeeper420's info: Jeep Liberty Forum - JeepKJ Country - View Single Post - Heater Core? What to check / costs?
2) Center Console: LOST JEEPS • View topic - HOW TO: CENTER CONSOLE REMOVAL
3) Dash: LOST JEEPS • View topic - HOW TO: DASH DISASSEMBLE
4) Pass Dash and airbag: LOST JEEPS • View topic - Passenger side dash D&A

Tools:
screwdriver - flat and phillips - electric screw driver will help...
3/8 drive ratchet, extensions, 10mm deep socket, 10mm regular socket, 13mm deep socket, 15mm deep and regular socket, 15mm ratcheting or regular end wrench
pliers for hose clamps
trim removal tool or similar prying tool (i like a putty knife) for dash panels
T-20 screwdriver for the steering column clamshell

Parts: (this was for my 2002 KJ, check to see what YOU need for your jeep by make and model)
Murray 93029 or equivalent



my steps (roughly) [note: i chose not to evacuate and disconnect the AC lines, this added some difficulty and resulted in some bent fins on the new heater core, i was ok with the bent fins in exchange for not having to pay for the AC system evacuation and re-charge.]

1) disconnect the battery
2) remove the center console (see above link) if you do this first you do not need the auto shifter in neutral to get the HVAC controls out
3) remove the HVAC controls and radio (note there is a kind of hidden screw that is in the pocket where the ash tray is) pry the surround out with putty knife. radio has 4 screws and 3 connectors on the back. HVAC panel has multiple connectors on the back, take your time here.
5) remove the cover panel up by the windshield, pry up at the edge closest to you as you sit in the seat

drivers side:
-remove the knee bolster under the steering column, the trim on each side of the column etc. as well as the plastic cover panel above the pedals
-remove the gauge cluster trim and the gauge cluster (phillips screws)
-lower the steering column, (2) metric hex head bolts (13mm deep socket on extensions) loosen these bolts until they are not protruding through the aluminum bracket (circled in red below)

-remove the bolts holding the steering column bracket in place 10mm hex head (black bracket with silver bolts in the picture below, bolts circled in blue above)

-remove bolts that go through aluminum bracket and into dash, you can access these from below the column, they go straight up and into the bracket. 10mm hex (one on each side of the column)

-remove the kick panel and then the bolts at for the lower dash bracket, these are 13mm.
remove the ground straps (8mm)

Passenger side:
-remove the glove box
-remove the kickpanel and plastic cover panel below the heater box.
- remove the horizontal trim below the air bag (phillips screws)
-remove the airbag cover (10mm bolts)
-WARNING: be careful not to hit, bump, or otherwise disturb the airbag with it exposed.
-disconnect the air bag wiring (i looked through the windshield while doing this so my face was protected.
unbolt the airbag 4 bolts total, set aside in a safe place.
-remove some of the vacuum lines to the heater a green one to a door actuator, and black tube/valve that clips to the heater box (see picture)

-disconnect and remove the dash speakers.
-remove the misc. 10mm bolts holding the dash to the firewall.

you should be able to lift and pull the dash towards the seats. the driverside does not need to pull out as far as the passenger.

now you should see the heater core. the OE unit is brown/beige in color, the replacement i got was black (the plastic end with the fittings.

in my case i chose not to unhook the AC (again please note you will damage your new heater core fins if you do it this way too). i cut the plastic tubes on the old heater core to make pulling it out easier.
i pulled the heater box into the jeep as far as i could with the lines attached, used pry bars to wedge it there. i also cut and pulled back the dash board insulation to make more space.

i then cut the tabs that hold the heater core in, just the two that are towards the inside of the jeep, i left the two towards the engine side, this allowed me to drop the heater core in at more of an angle.
(i noticed there are two holes in the heater box, and corresponding brackets with holes in the heater core so i used screws to hold it in)

i pulled out on the heater box one more time, and shoved the heater core in - some fins were bent.
since i was missing two tabs, i used some screws to help secure the heater core.
the screws i used:

the pictures are crappier than i thought, but here you can see the heater core installed, note the screws helping hold it down, because i cut the tabs off of the inner side of the heater box

reverse all the above steps and you are done.
i came out of this with only one "extra" screw, and everything working, so that is pretty good in my book. and i saved who knows how much over having a shop do the work!

 

[mikemar2020]

You do not need to replace the heater core!!! Save a ton of cash and a lot of your time and effort. The fix is cheap and can be done in a couple of hours. I have a 2007 Jeep Liberty and the heater core was leaking and had the terrible coolant smell in the vehicle when driving. I constantly needed to add coolant to the reservoir. This is what I did to fix my problem. I disconnected the rubber hoses that are connected to the heater core. I then did a thorough reverse flush to get all the crap out. Then I went to Lowes and purchased a cheap sump pump. I believe it was a 1/2 HP model that cost about $99. I previously purchased Bar's Radiator Stop Leak, Professional Strength Formula. The package has six large tablets. I recommend this brand because this formula was used professionally by GM for many years under a different trade name (see further below). I then proceeded to connect the appropriate fittings from the pump discharge to the heater core inlet. I placed the pump in a five gallon bucket of hot tap water with the appropriate number of tablets dissolved and ran a hose from the heater core discharge back to the bucket. I kept the bucket at the same elevation as the heater core. I then ran the pump for about 20 minutes in this configuration. After that, I just removed the pump and blewout the remaining liquid from the core, reconnected the radiator hoses and I was done. Now turn on your car and let it get up to temperature and turn your heater on and run it for maybe 15 minutes. My heater core no longer leaks, and I am a happy camper. Do NOT make the mistake of putting the radiator stop leak in your radiator as suggested by the package instructions.

The GM brand of radiator stop leak is AC Delco Part No. 10-108 12378255. When the pump was running I would create some back pressure by placing my thumb over the discharge hose. This helped force the stop leak into the little nooks and crannies where the leak was occurring. I did this setup because I did not want to go through all the work you showed. What a nightmare. I thought, if this did not work I was no worse off than when I started, I would still have a messed up heater core. However, I would not foul up my radiator, water pump, engine block, etc. which I have seen happen to some on YouTube when using stop leak products. Maybe I was just lucky but this did solve my problem. It has now been over a year and still working fine. The nice thing about this procedure is that if you find a leak starting again (hopefully not) you can do the procedure again.
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REPLY

 

[trktwo]

just got my heater core in. i dont see it mentioned, but on my 2004 liberty there is a 10mm nut inside the engine compartment. it is on passenger side to the left and below the hc in/outlet. taking that nut off gave me a lot more slack to wiggle the new heatercore in. i did not discharge my ac either.

thanks for the above, very helpful

 

[melizmc]

After heater core replacement

Okay, I had my heater core replaced and was 'misguided' by whom the work was being done.... that being said, my radio works, but there is no sound coming out of the speakers. I pulled the radio out, all the wires were plugged in where they should be on the back....Where in the hell is the problem?? Neither side works, so there must be a plug into the speakers from the radio?

 

[jeeptorino68]

Might get better response if you post in the main discussion are...but.
Are the tweeters hooked back up? Do you have the infinity sound system? Are ALL. The cables hooked up on the radio. If you have infinity stereo there are 2 plugs plus the antenna.

 

[JBDive]

So I have asked in a number of forums about the design of the heater core but have never gotten an answer.

I like most have had poor heat in my older Liberty. Everyone says replace the heater core, even the dealer, however when I state that when I back flush the core I am able to get a full stream of water going both directions (after the crap comes out).

The question is, is the heater core like a typical home AC with basically a pipe and fins or is it like a old school radiator with various narrow passages? Second can fluid run unobstructed from In to Out and Out to In if the core is still clogged, again much like an old school radiator where the various channels might be blocked but fluid would run across the top and sides where the passages were wider.

I'll add that I have back flushed my core a dozen times and each time I get this pink jelly out. First thing everyone says is you have mixed your AF but I have not. I just got a rebuilt engine in and when we took the old one out you could see this thick pink gunk all over the coolant passages. The engine, all hoses, radiator, water pump were all replaced and core was flushed again. As it's 90 outside I can't overly test the heat.

 

[Leeann]

Pink jelly means the HOAT was left waaaaay too long in the system without a flush. Coolant needs to be flushed and filled every couple years to keep the system operating best and to keep jelly from forming.

 

[JBDive]

Pink jelly means the HOAT was left waaaaay too long in the system without a flush. Coolant needs to be flushed and filled every couple years to keep the system operating best and to keep jelly from forming.

Which was likely the case however after the radiator was replaced and they said they flushed everything I should not have continued getting such jelly. When the engine was replaced I was able to look inside and in the engine cavities the slime was more condensed, almost a paste.

The original 02 manual said the AF was lifetime or something like that, haha.

I'd still like an answer as to how the heater core piping is setup. In looking at some aftermarket ones it appears there is a general flow into multiple tubes then back out via a unified port. It does not appear to allow a flow direct from in to out so if a flush shows no restriction then the tubes are open. I guess individually they could be clogged thus only part of the core is getting hot AF?

I wonder if it would be possible to fish something into the tubes from the firewall side? My gut says if the IN goes into a general opening with all the tubes aligned then the ones furthermost from the IN would get less pressure and flow and also be nearly impossible to fish something into.

Just to reemphasize, a back flush is clean and shows no restrictions. Does that mean to the entire core or just partially is the question.

 

[CorDog009]

I just did this today in my wife’s 07 Liberty. Went fairly smooth, I didn’t have a 5.5mm deep socket to take the grab handle bolts out with, so I made a trip to the parts store. Left the a/c in tact as mentioned.

 

[scottski]

I just got finished with replacing the heater core.
Not only that, while I was at it, I replaced the AC core.

Bad thing was, when put back (almost) all the way together, found out the blend door actuator was bad so I had to tear apart the dash again.

I also replaced the A/C compressor while I was at it. nothing like owning a car where both the A/c and heater was out.

Tearing out the seats were a pain, and I also ended up buying some used stock seat covers for the sport, and hit the you pick junk yard for some stuff. I cleaned out the interior while I was out it as well. Put the covers in the washing machine on the delecate cycle....

Also put in some seat heaters as well.

But really, Jeep should be embarrassed about that heater core and pulling the dash.
I had to remove the steering wheel, and I backed up the screws for the steering just enough to get the dash over .

I think I could do this all with my eyes closed now....

 

[KJownerX2]

Nice write up Jeeptorino68

 

[Mikesweet]

Do you absolutely have to pull the steering wheel? Any way around it? Doing an 07 tomorrow, any specialty tools needed?

 

[jeeptorino68]

Nope. Didnt need to on my 2002

 

[trucku]

Replaced the heater core in my 2003 Liberty. Did not evacuate my AC, so made it difficult to pull the heater box far enough to remove the old core. I optioned to cut the nubs on the core to remove it. The same issue would persist for the new core, so I optioned to do the same. I then connected 3/4" heater hose to it on the right inlet and 5/8" on the left outlet. This allowed me to push in the heater core and the flexibility of the hoses allowed me to bend them for the clearance and then push them through the firewall. Worked a charm.

Note:
You do not need to remove the passenger airbag. The dash is held in with 4 top bolts, 2 bolts on the lower console, and 2 bolts under the airbag. and two 10mm about 10 inches in, under the dash, one on each side of the steering column.
I used a ratchet strap to hold the right side of my dash far back enough so I could work relatively freely.

 

[DadOSix]

For the missing photos:

https://www.jeepkj.com/media/albums/heater-core.887/

They live in the above album.

 

[jeeptorino68]

For the missing photos:

https://www.jeepkj.com/media/albums/heater-core.887/

They live in the above album.

thanks for posting the link. sorry for the busted photos in the original, but i think you can connect the dots between the post and the photos in the album

 

[DadOSix]

Hey Kyle,

thanks for this write up!
I had the gist of it without the pictures, but they were a lifesaver on the hidden fasteners.

this is our 2nd KJ. Just picked this one up from a frustrated woman as a project car for my son who sets about drivers training in a few months. She bought a newer car as this jeep has a bunch of ‘little’ issues and couldn’t see putting more money into it. The heater core was the last straw for her.

jeff

 

[Trainmaster]

My 2005 with 164,000 miles' heater core has a small leak. Upon turning on the defroster I get some mist and that smell of anti-freeze, but there's no water leaking down. Today I tried plugging the leak following mikemar's procedure above. I dissolved five ACDelco GM "Cooling System Seal Tabs" in three gallons of hot water and circulated it with a pump through just the heater core for a half hour.

The tablets are made of - get this - Ginger, Tumeric, Almond nut shells, and Sodium Carbonate. Let's see what happens. I'll let you know.

 

[David13]

It will be interesting to see. I'm looking for a Liberty and I had my young lady friend check for a leaky heater core on all of them that we looked at.

I saw a video on it, and it doesn't look like an easy job.

I have done maybe 5 heater cores before, but that was when I lived in Los Angeles and I had a neighbor who helped and did a lot of the steering wheel and dash removal. About all I had to do was the engine area stuff, hoses, etc.

On none of them did we have to touch the a/c.

I can't remember what it was, but I did do one when all that needed to come out was the glove box. That's the way to design it.

dc

 

[Trainmaster]

I will let you know if this stuff worked. Give me a few days to see. From what I see, replacement in these cars isn't as bad as many. You can leave the steering wheel in and drop the column down. You can leave the a/c lines charged, unmount them from their retainers in the engine bay and pull the heating box out enough the get the heater core out.

The question is whether you can pull it out enough to get both heater core tubes clear of the firewall. Trucku above cut them off and fastened hoses. He also trimmed some mounting tabs. I've heard that others did not have to do that.

Nice thing about the job is the hoses slip right off. Fords have some "quick connects" that are very difficult to reach and take hours to get free. It's all clean work with simple tools, so I suspect if you do your research you can be done in four or five hours.

I'll let you know how the sealer worked. Merry Christmas!