Note from Stu: A big thank you goes out to Taka. I received an e-mail from him after he had swapped the heater cored on his ’01 TJ 4.0L. He took the time to document his swap using 93 commented photos. Better yet, he wanted to share this information with his fellow Jeepers. Here is his e-mail explaining it…..
Hi Stu,
First of all, thank you so much for maintaining such an awesome website for Jeep owners. I had, and will have to, pay thousands of dollars for my TJ without your site.
I was thrown into despair after realizing that mysterious strawberry-color droplets inside my jeep were actually leaked antifreeze from the heater core. And I came across the best detailed description of how to fix this issue on the internet, which was the write-ups in your site. I finally decided to DIY after my TJ almost had an overheat. Although I am in an amateur side for car maintenance, but the write-ups encouraged me to do so. It guided me almost in the perfect way, but I had to spend a lot of time to understand unfamiliar and specific terms (I am a Japanese and not English-native) and figure out which bolts/nuts to remove.
I took pictures in each step and created a photo-based manual. I would like to ask you to post this in the heater core replacement section since it would supplement the write-ups and could be helpful especially for people who never have done Jeep maintenance but having a leaky core problem. It should work at least for Wrangler Sport 4.0L (2001, manual shift) but could be informative for all the TJ models. The manual is in my web album and anyone can take a look. I am happy to have any comments and corrections. I will maintain them as long as I pay for the Google storage service…Please let me know if you have any problem to see the pictures.
Again, I appreciate Stu and all the people who participated in the heater core replacement write-ups. Jeep forever!
Best,
Taka and Taka’s Jeep (TJ)
Update: 03/02/2019 Taka recently contacted me to inform me that the hosting page he had his photos on was being discountinued. I asked him if I could download them and host them on my site. He graciously agreed and commented that he was glad to see his work would continue to be made available to other Jeepers.
NOTE: When removing the steering column, DO NOT allow the steering wheel to spin within the column assembly as it will damage the clock spring which will then need to be replaced! If the clock spring is damaged, you see issues with your horn, air bag light and possibly the instrument cluster when you reassemble your dash. Use a bungee cord to secure the steering wheel so it does not rotate.
And lastly, if you haven’t seen it, there is another heater core swap write-up on this site.
Here is Taka’s photos and comments…..and thanks again to my friend for allowing his work to be shared here.
Typical antifreeze leak in driver’s side. If you see this, you need to ask yourself if you don’t mind to spend over a thousand bucks at dealer to get a peace of mind. Otherwise, here is a set of photos that might help you! FYI, Mine is Wrangler Sport 4.0L (2001, manual shift) but this protocol may be applicable for all TJ models.
Exif_JPEG_PICTUREAntifreeze leak in passenger’s side. I started disassemble without draining antifreeze.
Exif_JPEG_PICTUREDisconnect and remove battery. This should be done first, as you know!
Exif_JPEG_PICTURERemove the two Phillips-head screws (arrows) from the knee blocker and pull the panel towards you to remove.
Exif_JPEG_PICTURERemove two Phillips-head screws (the left side hole is indicated) from the lower trim piece of the steering column.
Exif_JPEG_PICTURERemove the lower heater hose. I plugged the end of hoses because I did not drain remaining antifreeze.
Remove the L-shaped evaporator drain tube that protrudes from underneath the evaporator canister.
Remove one of the HVAC housing-to-chassis nuts using a 7/16 socket. The one in the left side of blower fan was removed in this pic.
Remove second HVAC housing-to-chassis nut using a 7/16 socket. The one in the upper right of blower fan was removed in this pic (this also holds a bracket for accumulator canister).
Remove third HVAC housing-to-chassis nut using a 7/16 socket. The one in the lower right of blower fan was removed in this pic. The accumulator canister becomes loose after removing the second and the third nuts. You may disconnect AC lines after this.
TJ Heater Core Replacement #2
by Taka Sokabe
Remove the forth HVAC housing-to-chassis nut using a 7/16 socket. The one above the engine was removed in this pic.
Remove The nut holding the plastic drain duct using 7/16 wrench. This is located about 1-foot below the fourth nut and difficult to reach. After removing the drain duct, you will see hidden fifth nut holding HVAC unit (arrow).
The drain duct can be removed by pulling it down.
The drain duct. You can see the hole holding the duct to the fire wall.
Remove the fifth HVAC holding nut using 7/16 wrench. Be patient!
TJ Heater Core Replacement #2
by Taka Sokabe
Remove the 2 screws mounting the floor duct to HVAC unit using a 5/16 socket.
Remove the 1 rear screw mounting the floor duct to HVAC unit using a 5/16 socket. You barely see it but can reach from driver’s side. After removing all 3 screws you can pull it towards driver’s side.
Remove the screw holding the HVAC unit to the firewall bracket, near the fuse panel, using a 5/16 socket or wrench (a holding ring for air duct was attached on the top of the bracket).
Remove the upper air duct in the passenger’s side from HVAC unit. No screws or tubs.
This is the upper air duct.
TJ Heater Core Replacement #2
by Taka Sokabe
Pull the HVAC unit towards you a little bit (until 5 bolts pulled out from the fire wall) then pull the right side first as indicated by an arrow to remove the whole unit.
The HVAC unit was removed. I did not cap the end of two heater lines and some antifreeze spilled on the floor when I removed the HVAC unit.
The positions of 5 mounting bolts are indicated. A big round hole in the right is for blower fan and a rectangle hole in the middle is for heater/AC lines.
I found an unused connector just underneath the center floor duct in my TJ.
Top view of HVAC unit.
TJ Heater Core Replacement #2
by Taka Sokabe
Remove all the 13 screws holding the upper and lower housings of HVAC unit using 5/16 nut driver. This pic shows the two of them on the blower fan side.
Two screws near the heater/AC lines are shown.
One screw right next to the heater lines is shown.
Two screws near vacuum pumps are shown (opposite side of blower fan).
Another screw near the vacuum pumps.
TJ Heater Core Replacement #2
by Taka Sokabe
4 screws on the dash side are shown.
Remove two small tubs using flathead driver.
Cut off and remove insulator foam carefully using sharp knife. I will reuse this later.
Remove the green harness connector and the black box hooked on the dash side of HVAC unit.
TJ Heater Core Replacement #2
by Taka Sokabe
Unplug the harness underneath (passenger’s side).
Unplug the harness from heater/AC flap motor located underneath (arrow). Then remove the motor to release the harness by unscrewing 3 bolts (oval).
The motor was removed.
The first set of harness is almost free from the HVAC unit. The other end is connected to blower fan.
After cutting off the upper half of foam on the blower fan trim (the pic will be shown later), remove 3 bolts holding blower fan using 5/16 socket (oval). Remove the fan with harness.
TJ Heater Core Replacement #2
by Taka Sokabe
Disconnect the green vacuum line from the pump.
This pic show how the second set of harness runs on the top side of the unit. 3 disconnected ends are shown (ovals).
Disconnect 4 vacuum lines from pumps. Remove entire harness.
Remove the top housing. Note that the lower half of foam for blower fan trim is left intact.
My deadly leaking heater core was finally removed. Clean up the inside of HVAC unit and the AC unit. The styrofoam under the AC unit was totally worn with antifreeze but I washed thoroughly and reused it.
TJ Heater Core Replacement #2
by Taka Sokabe
New heater core was installed. I purchased heat-resistant foam tape to secure the core (arrows). An oval indicates the end of flap, which should be inserted into a hole in the upper housing.
The heater core was supported by this unique shape plastic part.
Place the upper housing trying to insert the flap end to small hole in the upper housing (oval). This might needs some patience since you can’t adjust the position of flap end from the top. The other end of flap protrude from lower housing and you can test if it moves smoothly by turning it with your fingers. Once you succeeded to close the unit completely, put all the 13 screws back.
Adjust the position of heater line so that you can secure it with a screw (oval).
Put some glue to reattach the foam to the upper housing. Don’t forget to embed harness in the slit first.
TJ Heater Core Replacement #2
by Taka Sokabe
The harness is held behind the foam.
Put glue on the foam for heater/AC lines.
The foam was attached. Now you’re ready to reassemble! Simply repeat all the steps in the reverse order. Take your time and have a happy jeep life!
TJ Heater Core Replacement #2
by Taka Sokabe
Remove the upper trim case being careful not to break the hazard switch.
Unplug two electrical connectors from the bottom of steering column.
Unplug one electrical connector from the left hand side of steering column. The red tab must be unlocked (arrow) before disconnecting.
Unplug one electrical connector from the upper left hand side of steering column. The red tab must be unlocked before disconnecting.
Unplug one electrical connector from the upper right hand side of steering column. The red tab must be unlocked before disconnecting.
TJ Heater Core Replacement #2
by Taka Sokabe
Detach the harness clip from the holder on the upper side of steering column.
Remove the pinch bolt securing the steering shafts using a 13mm socket. This pic was taken from the bottom side. Set the steering straight so that you can reach to this bolt easily through notch.
The securing bolt was removed.
Remove the left side nut securing the steering column to the cross-member of the firewall using a 13mm socket.
The nut was removed.
TJ Heater Core Replacement #2
by Taka Sokabe
Remove the right side nut in the same way.
Remove the nut securing the steering column to the top of the firewall using a 13mm socket.
The nut was removed.
Remove the right side nut in the same way while holding the steering column. Mine doesn’t come with tilt/telescoping function so the those procedure may be different from yours.
After detaching steering column unit, you can see lower steering shaft (rectangle), two bolts on the cross member (arrows) and another two on the upper fire wall (oval).
TJ Heater Core Replacement #2
by Taka Sokabe
The upper steering shaft (rectangle) and holes for cross member (arrows) and fire wall (oval). Do not loose black plastic parts (oval).
Protect the upper steering shaft by wrapping with something clean like saran wrap.
The driver side looks like this after removing the steering column assembly.
Disconnect the driver’s side defrost hose at the central duct.
The wiring harness connectors (rectangles) on the left side of the inner panel will be disconnected from now. See the details in the following pics.
TJ Heater Core Replacement #2
by Taka Sokabe
Harness (rectangle) were disconnected. Red/white and yellow connectors (oval) are from steering column unit. I left the connector untouched (arrow).
Remove gray connector behind. Slide the red tab first to unlock (arrow).
After removing glove box in the passenger’s side, disconnect the heater/AC vacuum harness connector. As you disconnect it, you’ll hear the air pressure being relieved.
Disconnect green harness connector on the right side. Slide the red tab first to unlock.
Disconnect radio antenna.
TJ Heater Core Replacement #2
by Taka Sokabe
Unplug the yellow harness connector and disconnect the passenger-side defrost hose at the central duct.
Remove the two nuts from underneath the passenger’s side air bag using a 15mm socket.
Remove the upper cover that is held with tubs from dash.
Remove the three Torx-head screws from driver’s side of the dash.
TJ Heater Core Replacement #2
by Taka Sokabe
Remove the four nuts along the window where the dash is mounted using a 10 mm socket. This pic shows the far right one.
Second one from the right was removed. The same set of two nuts is in the left side.
Put the shift lever to 4th gear before starting this step if yours has manual stick. Lift up and gently pull the dash unit. It is much easier with two people.
Pic from passenger’s side after removing dash unit.
Pic from driver’s side after removing dash unit.
TJ Heater Core Replacement #2
by Taka Sokabe
Disconnect the vacuum supply line connector, which is right beneath the AC lines in the engine room.
“CAUTION: discharge AC refrigerant before disconnecting AC lines! This needs special tools or professional support.”Remove two AC line connector covers.
Disconnect AC lines. Insert 5/8 disconnecting tool to small and 3/4 one to large line, respectively. I used “Lisle 37000 Air Conditioning/Fuel Line Disconnect Tool Set”.
While inserting the disconnecting tool, pull the line on the right side until you see gasket (green in this pic). This step gets easier after removing two heater/AC unit mounting bolts securing AC accumulator (beneath the two A/C lines in the pic), by which the large line becomes more flexible. If you want to dismount AC accumulator, skip this and do the following several steps first….
After relocating the spring clamp (arrow) using a channel-lock pliers, disconnect the upper heater hose. I coated the connection part with hot soap water and twisted the hose left and right using channel-lock pliers. Covered the hose with towel to prevent from damage.