Author Topic: Gen 2 Heater Core Replacement and differences  (Read 1918 times)

IncorpoRatedX

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Gen 2 Heater Core Replacement and differences
« on: July 19, 2017, 12:34:55 PM »
I'm starting this thread as a bit of a place-holder. I'll be ripping into my Gen 2.5 Montero (1999) and replacing the heater core this fall... there's been some discussions among local crowds, sometimes internet folks about the timeline of Gen 2's, mitsu might've been cutting costs as time went on, taking lower bids on out-sourced parts.

If you know much about auto manufacturing, you're probably aware of what it takes to make a vehicle, heater cores and radiators and intercoolers from these guys, shocks from those guys, ignition parts from those other dudes, transmissions often from somewhere else, it all comes together and youve got a working unit, over time if that unit proves popular, especially if it's cult level popular, you're able to retain the same chassis and drivetrain but cut costs through writing specs to bid or reverse engineering and producing things in-house. it's a churning industry with too many cooks in the kitchen and often far too driven by the accounting department.

It's often been said that when accounting wins against engineering in the argument for a product the consumer ends up losing. this is almost always the case, but even when engineering wins, the customer still suffers because the higher costs of the quality parts are marked-up and passed on to the consumer. So you either pay up for good stuff or pay little for future effort/costs.

Almost every Gen 2.5 I come into contact with ends up needing a heater core at some point. Most of the southwest guys have theirs blocked off. This is fine for 9 months of the year, for 3 months or northern trips, or major road trips, it will suck a bit.

The idea I have is to pull the heater core from my 99 and retrofit a 1994 unit after comparing them, I'll be documenting the differences and probably going to a local radiator shop to have the 1994 core beefed up a little, if possible.

If any of you have any current documentation on heater cores for gen 2-2.5's or you can share a photo of one you've removed from a truck, maybe your truck, please feel free to post, the info that would be good to share is:

Year of montero
Did the unit fail?
Manufacture if stamped on end tank
detailed photos of the seams


jaccox

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Re: Gen 2 Heater Core Replacement and differences
« Reply #1 on: July 20, 2017, 07:38:00 AM »
Alright so I tackled this in my '99 at the end of the winter this year. I didn't take many detailed pics just a couple of the whole dash disassembled tornado wreck pics. If my memory serves correct you've done this job before with Toasty in his '99 correct? I will say mine was not leaking from the heater core once i finally got to lay eyes on it. Rather the design of the original was the heater core had the pipes welded onto the core itself and then extended a few inches and then a rubber piece of hose connected that pipe to the pipe leading to the engine bay. The leak was at the part where the rubber hose connected the two brass pipes. What i believed caused the leak was the fact that they used a single wide clamp to hold the rubber on both ends, instead of a clamp for each end of the rubber connector pipe. That was my case though every other one i've seen is the actual core leaking. The updated core i purchased from parts.com was totally different in the sense that the pipes are solid from the firewall to the core itself and connect using o-rings and pressure clamps at the flange of the heater core. I will say it came with a new housing box, so hopefully the '94 core just slides right into the '99 box and has the similar 2 piece pipe assembly and not the 1 piece like the aftermarket. Sorry I don't have pics for reference and just a mess of words, but i hope that helps.
1999 Montero. 33x10.5x15 General X3's. 4.90's w/rear locker. Full armor. ADD idler arm. ADD 1.5" complete lift. Siberiean Bushings everywhere. 150W alternator with upgraded 4 AWG leads and grounds. 2nd Battery in the rear for camping stuffs to come.

IncorpoRatedX

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Re: Gen 2 Heater Core Replacement and differences
« Reply #2 on: July 20, 2017, 09:22:57 AM »
Good info Josh. Toasterbox has yet to replace his 99's. we talked of have a heater core party but his schedule and mine are always a mess.

I did however remove the unit from the 94 when parting it out. I've torn down more complicated mitsu dashes so the work involved isnt too much a concern, just documenting what the best unit or best method, best modification to install will be. I will likely find a way to eliminate any sort of rubber coupling. I'll get a photo of the 94 unit here in the next few days to add some photo content to this thread.

TOASTY

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Re: Gen 2 Heater Core Replacement and differences
« Reply #3 on: July 20, 2017, 12:57:24 PM »
 We tore down the 94 dash without breaking anything in 2 hours i think.

IncorpoRatedX

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Re: Gen 2 Heater Core Replacement and differences
« Reply #4 on: July 20, 2017, 01:05:57 PM »
You're thinking of removing the dash. I didn't remove the wiring harness and HVAC stuff until later, it's a bit more than two hours.

jaccox

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Re: Gen 2 Heater Core Replacement and differences
« Reply #5 on: July 20, 2017, 01:40:58 PM »
It was my first rodeo with tearing a dash out and it took me like 4 hours solo to get the dash out... Once you accept the fact that if it can be removed it shall be removed and you just start piling stuff up in the garage the box/core will slide right out in no time. I can see having disassembly done in a little over 2 hours after having done it before. Most of my time was spent trying not to take everything off and get it out when in reality if you can fit a socket get it out of the way. Also crack open that Evap box and blower motor and clean those out with a shop vac. Mine were loaded with garbage. I would have saved my core but I mangled the brass pipes so badly I didn't even want to take it to the rad shop.
1999 Montero. 33x10.5x15 General X3's. 4.90's w/rear locker. Full armor. ADD idler arm. ADD 1.5" complete lift. Siberiean Bushings everywhere. 150W alternator with upgraded 4 AWG leads and grounds. 2nd Battery in the rear for camping stuffs to come.

RaptorReed

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Re: Gen 2 Heater Core Replacement and differences
« Reply #6 on: July 21, 2017, 09:08:33 PM »
Just a extra note, the changeover to the newer heater core was in mid 95 according to ASA the last time i checked it.
Tim
1994 Monterp SR
1992 Galant VR-4
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Justice

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Re: Gen 2 Heater Core Replacement and differences
« Reply #7 on: July 22, 2017, 10:25:11 PM »
Random info, the 95 I Sold to JBFP had coolant smell in the cab, which I assume was the heater core vaporizing coolant. The 99 I believe you have now had a clogged core when I got it, no heat at all. I was in north carolina at the time and it gets cold there. I disconnected the heater hoses and ran CLR mixture through it until I was able to get decent flow. Heater worked OK after that, not the best but it worked.

My current 99 leaks, I cant see any moisture but I can smell it. I suck at putting interior parts back together, so I'm considering bypassing it.

B2Montero

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Re: Gen 2 Heater Core Replacement and differences
« Reply #8 on: October 22, 2017, 10:49:25 AM »
I'm having flow issues on my 96 SR. New T stat and flushed a couple of times. Still not very much heat though. Did the CLR make that much diffference?  And did you fill the core with it and leave it sit for a while?   Tips? Want to try options before I have to do a dash-ectomy.

Thanks!

JohnnyBfromPeoria

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Re: Gen 2 Heater Core Replacement and differences
« Reply #9 on: October 22, 2017, 04:02:42 PM »
I'm having flow issues on my 96 SR. New T stat and flushed a couple of times. Still not very much heat though. Did the CLR make that much diffference?  And did you fill the core with it and leave it sit for a while?   Tips? Want to try options before I have to do a dash-ectomy.

Thanks!

Before you go to all that trouble, make sure your blend door is operating correctly. Remove the glove box, stick a flashlight up towards the top of the assembly behind the opening and turn the temperature knob so you can see the cable that moves as the knob is turned. On my 95, if I want full heat, I have to reach up in there and push the lever fully because the cable stretched or came loose and doesn't move it all the way by itself. Lots easier than replacing your heater core.

John B.
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95 SR, 35x12.5-15 on 8" steelies, 2" BL, stuff cut off, stuff welded on, lights, sound, front ARB pending
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83 "Dodge" Power Ram 50, a bit lifted, way slow and gets more comments from random people than the other two put together
'95 Montero SR. Pretty much stock, Trail Gear Sliders, ADD skid plates, Stereo by Shovel, Timing maintenance by Pa_Jero

concealer404

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Re: Gen 2 Heater Core Replacement and differences
« Reply #10 on: October 22, 2017, 05:07:21 PM »
I still have yet to figure out how to remove the center vents in the dash...
1998 Montero Winter Package (For Sale)
1994 FZJ80 Land Cruiser (Wife's)
2006 V8 4Runner Sport Edition (Mine)

PA_JERO

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Re: Gen 2 Heater Core Replacement and differences
« Reply #11 on: October 22, 2017, 07:10:07 PM »
Get to the center vents by removing the whole dash. Not an easy task, but if your motivated, it can be done in a day.

concealer404

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Re: Gen 2 Heater Core Replacement and differences
« Reply #12 on: October 22, 2017, 07:28:34 PM »
Get to the center vents by removing the whole dash. Not an easy task, but if your motivated, it can be done in a day.

I haven't been able to figure out how to remove the dash.... without removing the center vents.  :P
1998 Montero Winter Package (For Sale)
1994 FZJ80 Land Cruiser (Wife's)
2006 V8 4Runner Sport Edition (Mine)

Cosmos99

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Re: Gen 2 Heater Core Replacement and differences
« Reply #13 on: February 27, 2019, 08:29:50 AM »
So I have a little moisture on the passenger side corner of the windshield and can smell coolant.  Going to tackle the core asap on Black Betty.  Did anyone find out if the 94 cores fit in a 99?  Any recommendations on a procedure with the airbags?
Gen 1 1987 Radier 2.6 ( sold )
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99 Montero overland ready.

TOASTY

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Re: Gen 2 Heater Core Replacement and differences
« Reply #14 on: February 27, 2019, 09:07:36 AM »
The '94 core fits the '99, also found out the Mitsu ones are brass but commonly replaced with aluminum cores. The aluminum cores don't last as long and typically the brass cores leak at the hose. The air bag code needs to be cleared with a MUT2 or equivalent, it's not a terrible job. About 4 hours down and up, i recommend you buy an HVAC controller and vents to go along with the job.