Heater Core Replacement/Allisport Upgrade

JimC

Super Moderator
Staff member
Replacing a heater core is not a terribly difficult task, but it can be annoying and fiddly with the fender in place. Seems every vehicle has combination of fuel lines, AC hoses, wiring, etc that makes getting the actual box out quite difficult. There are only 4 fasteners holding the box in but even these can be a real pain.

The fasteners on top actually don’t have to be removed all the way, since the top of the bracket is open. The 6mm bolts on the bottom of the box can be downright terrible. Not only is there no clearance for a socket, the nuts are inside the footwell and you can‘t hold them in place without a helper unless you remove a door. And if you have an AC unit in the footwell, then you might not be able to reach these nuts at all. Then you have to carefully drop the AC unit to reach behind it. I dealt with this problem by installing rivnuts at the lower locations.

Again, this box had no coolant in it since I was just upgrading the core to an Allisport one while the engine was out. One thing that adds fun to this job is the fact that you have to twist and maneuver the box all over the place to remove it with the fenders in-situ. That will ensure you dump coolant everywhere unless you very effectively plug the tubes. Unfortunately that probably won’t be possible because there is a high likelihood that you’re only doing this job because one of the tubes snapped off...

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JimC

Super Moderator
Staff member
This heater core model has tubes exiting to the front. Earlier ones exited to the side. No big deal, as long as your box looks like the one shown then either model will work assuming the hoses will reach. Earlier heater boxes have tubes that come out and turn down. I dont think later cores are compatible with these boxes.

Anyhow, the core is easy to separate once you take out about 20-ish screws holding the four retaining plates located at the top and bottom of the box. There is a fair amount of foam in the box, some will come out with the core, and you’ll need some thin foam on hand to replace this. There is also a large strip of dense foam that fills a gap on one side of the core, try to maintain this intact or you’ll be looking for a suitable replacement. It’s worth taking a moment to inspect the condition of the foam on the two blend doors. Go ahead and replace this if it is all crumbling and nasty.

If you’re installing an Allisport core, you’ll notice that it’s more than a centimeter thicker than the original and you’ll need to relieve the retaining plates about 6-7mm on each piece. I had another set that I had prepared earlier and had powder-coated.

Note the Allisport core comes in bare aluminum. I had the top and bottom powder-coated to make it all black and prevent the unsightly surface corrosion that inevitably occurs twelve seconds after you install a shiny new aluminum part.

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JimC

Super Moderator
Staff member
You’ll need to wrap the new core on three sides with foam at the top and bottom in order to seal up the protruding sections. I was careful to ensure the foam didn’t stick out once everything was put back together, but LR never did. Squishing the foam with the retaining plates is at least a good visual way to ensure you’ve got no air leaks.

Reinstallation into the truck is no worse than removal. I cleaned up the box and replaced some of the parts with powder-coated bits just to get rid of some of the corrosion. I finished things off with a new sticker. Not all vehicles had these pointless “buy only genuine parts”
labels, but I really like applying stickers.

Reattach your coolant lines and your heater cables and things should be much improved.

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JimC

Super Moderator
Staff member
It does, I used it for a couple years in my crew cab. The air has more time to contact the surface as it blows through the core.
 

Z.G

Well-known member
Did they discontinue those forward facing versions? Cant seem to find them anywhere
 

JimC

Super Moderator
Staff member

click on the LHD version, it changes the picture to the forward-facing tubes.

it does say “email for availability“ …
 
This is a really valuable post JimC. Thanks very much for the efforts! I will upgrade to that Allisport core. Do you have any recos for an upgraded blower too?

May I ask where you sourced the new sticker?
 
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