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View Full Version : Jeep Wrangler (TJ) Heater Core Leak!



Brian
February 15th, 2018, 10:47 PM
I've been wheeling the better part of 25 years in a '79 Scout and pretty much tried as best I could to be as knowledgeable as I could on it's mechanical upkeep and maintenance. Along the way I managed to convert it to 100% propane and eventually a 5.3L Chevy and driveline swap. Then last September I sold the rig (too many reasons to list) and 'got in step' with the Jeep mafia and bought a 2004 Wrangler Unlimited. I mean, what's this 'Jeep Thang' all about and why wouldn't I understand? It's in pretty good shape with just some easy wheeling and mild mods to its credit. Things were going pretty good with it and I began to daydream of the first real wheeling trip I'd take with it.

But... It always had a 'lil bit of a 'funky' smell to it. I just attributed it to a some 'mudding' and lack of complete clean up. Or maybe all Jeep soft tops harbored mildew/moldy/rusty plumbing pipe odiferous emanations. I mean, what do I know about Jeeps anyway?! Maybe all Jeep window's fog up when you use the heater. No such luck...I had the dreaded heater core leak!!

I Googled up some info about the issue and to my surprise I found what at first I thought was an internet hoax. Numerous sites and members were detailing removing the entire dash down to the firewall just to get to a heater core. Hahahahhahaha, I thought! What a bunch of jokesters! But the joke was on me. To my dismay these tales of woe were honest and accurate. I, a n00b Jeep owner, was about to embark on a journey that would lead me to the brink of insanity and a newly developed nervous tick!

Credit to the following sites and video's (listed below) for leading me through the process. Rather than 'reinvent the wheel' I'll just say these sources will get you through it if you ever have the need. However, I'll say this; most info in regard to the removal of a Wrangler heater box deal with the 1997-2002. A change happened around 2003 to the design of the box, but the info supplied about the 1997-2002 box removal will work for 03-06.

Notable exceptions: 03-06 Wranglers do not have the same pigtail/harness set up under the dash. There are three harness's to unplug, but they are quite obvious and below the steering column, near the drivers kick panel. Some write-ups claim there is no need to remove the steering wheel and dash completely. That MAY work, but since I was working alone I decided to remove everything so I would be able to 'manhandle' the dash and have maximum flexibility during removal and replacement. Also, I decided to change out the AC evaporator while I was in there. Added a few $$, but since I was in there...why not.

I'll just say this; I was shocked to discover this 'dirty little secret' about my Jeep. But, after all the angst and feelings of dreed over this repair passed and I got into it, it went pretty well. Took me about 3 days to disassemble everything, but I was really taking my time trying to pay attention. Plus, I had to get my AC purged before I started. Going back together took about 4 hours!

Here are the 'crime scene' photos:

Take your doors off, makes it a 'lil easier

https://i.imgur.com/YrtzeOd.jpg

Removing the steering wheel trim

https://i.imgur.com/IkzZakl.jpg

Steering wheel removed

https://i.imgur.com/jzpGssK.jpg

Remove your dash-yes, it comes out just like that in one piece

https://i.imgur.com/tcc4KgD.jpg

Now you're down to the heater box

https://i.imgur.com/tSINwmi.jpg
https://i.imgur.com/dMuDPy1.jpg

Remove it and your down to the firewall

https://i.imgur.com/xrEZMih.jpg

The leaking heater core

https://i.imgur.com/Aa8MYdQ.jpg

The new OEM Mopar parts that went back in

https://i.imgur.com/hCUmDem.jpg


Sources:

https://www.youtube.com/watch?v=XXwi9tYzuCg

http://www.stu-offroad.com/engine/heatercore/heatercore-1.htm

http://www.stu-offroad.com/engine/heatercore/heatercore-2.htm

Getaklu
February 16th, 2018, 06:49 AM
Looks like a bit of a PITA. You handled it like a trooper and thanks for the information and forewarning.

open_circuit
February 16th, 2018, 08:28 AM
I wonder what the funky smell is like. My 2005 LJ has a rather unique "hot" smell after running a bit.

Brian
February 16th, 2018, 08:30 AM
I wonder what the funky smell is like. My 2005 LJ has a rather unique "hot" smell after running a bit.

It was like a dank, rusty plumbing pipe kinda thing. I caught mine before it began leaking into the floor but it was still enough to fog the glass which was the real tip off.

Java
February 17th, 2018, 06:28 AM
I may be doing this soon too, I don't have a leak but as I understand it the lifespan of the TJ/LJ cooling system is 12-15 years, then the radiator and heater core do this. I just had a radiator leak and am kicking myself for fixing the radiator instead of replacing it. I'm considering replacing both, along with the waterpump, thermostat and all the hoses while it's apart.