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heater core woes

gto4evr

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July 19, 2007
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Year, Model & Trim Level
'98 XLT
I just embarked on the ridiculous journey of tearing the truck down to the frame just to change a heater core on a 98 explorer! I've accepted my fate of the 20 hour job ahead of me with my factory manuals at my side.

I've gotten the wheel off, torn into the column, have just about everything disconnected and I'm at a roadblock with the airbag sliding contact. Why does this have to come off? I don't see any reason to remove it since I'm at the point where it's just the bolts holding the column on. All the electrical connectors are disconnected. The air bag sliding contact wiring is already off the truck at the bottom connector and as far as I can see, it's just along for the ride when the column comes out. I hate doing things I don't understand and this is one of them. For that matter, I can't even see why the wheel and the ignition lock cylinder needed to come off.

Anyone got some insight before I take this piece off for nothing and end up screwing it up?

Thanks,
Dennis
 



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Yeah isnt the heater core on the passenger's side? The coolant goes through two holes on the driver's side, right under where the computer sits:

empty_firewall.jpg
 






izwak, yea it's there all right, unfortunately Ford decided it really didn't give a crap how to get it out and the dash has to be removed to gain access to it. I had an 86 F250 that took me about 10 minutes to change. It was the first time I gave any respect to "new car" designs (I live in the 60's for all my every day drivers) So much for that since by 98 explorer times they decided to make it near impossible to change. I've got factory manuals as well as a copy of the ALLData online manuals and they confirm AC evaporator core housing has to come off on the engine side, steering column and entire dashboard need to come off on the inside. This is quite a job for a backyard mechanic.
 






izwak, yea it's there all right, unfortunately Ford decided it really didn't give a crap how to get it out and the dash has to be removed to gain access to it. I had an 86 F250 that took me about 10 minutes to change. It was the first time I gave any respect to "new car" designs (I live in the 60's for all my every day drivers) So much for that since by 98 explorer times they decided to make it near impossible to change. I've got factory manuals as well as a copy of the ALLData online manuals and they confirm AC evaporator core housing has to come off on the engine side, steering column and entire dashboard need to come off on the inside. This is quite a job for a backyard mechanic.

that's one thing me and my friend laugh about newer cars. the stuff that shoudl be simple is hard. at least in our 93 blazer and 93 explorer, it's easy to get to. i've never had to change my heater core, but i know it's about 10 minutes to get out.
 












izwak, yea it's there all right, unfortunately Ford decided it really didn't give a crap how to get it out and the dash has to be removed to gain access to it. I had an 86 F250 that took me about 10 minutes to change. It was the first time I gave any respect to "new car" designs (I live in the 60's for all my every day drivers) So much for that since by 98 explorer times they decided to make it near impossible to change. I've got factory manuals as well as a copy of the ALLData online manuals and they confirm AC evaporator core housing has to come off on the engine side, steering column and entire dashboard need to come off on the inside. This is quite a job for a backyard mechanic.

This shortcut may help(you or others), if you are careful with the A/C lines the a/c does not have to be discharged and the evap box can stay. Take out the cruise control, fluid tanks, and a bolt that sticks up near the fan, get it out from under the wheel well. Remove 4 nuts with I believe are 11 mm deep sockets. 3 are on the engine side of the firewall (one is hard to get to about a foot under the heater lines, one inside by the passengers foot near the inertia switch. Then carefully pull back the evap box to expose the nuts holding the internal heater box. Remeber the A/C lines are attached. The nuts you need to take off are on the same studs as the nuts you took off for the evap box. If you have alot of trouble you can always discharge the A/C if you cant get to these bolts...just a thought.

Also, when you are in there REPLACE YOUR BLEND DOOR!!!!!!! or don't bother doing this repair! That makes this repair worthwhile. They are available at NAPA for 10 bucks, either cut the top of the box with the supplied kit/template or work the door out of the box (yes its possible with some slight trimming of the door, usually 1/4" off the bottom corner opposite the pivot).
 






This shortcut may help(you or others), if you are careful with the A/C lines the a/c does not have to be discharged and the evap box can stay. Take out the cruise control, fluid tanks, and a bolt that sticks up near the fan, get it out from under the wheel well. Remove 4 nuts with I believe are 11 mm deep sockets. 3 are on the engine side of the firewall (one is hard to get to about a foot under the heater lines, one inside by the passengers foot near the inertia switch. Then carefully pull back the evap box to expose the nuts holding the internal heater box. Remeber the A/C lines are attached. The nuts you need to take off are on the same studs as the nuts you took off for the evap box. If you have alot of trouble you can always discharge the A/C if you cant get to these bolts...just a thought.

Also, when you are in there REPLACE YOUR BLEND DOOR!!!!!!! or don't bother doing this repair! That makes this repair worthwhile. They are available at NAPA for 10 bucks, either cut the top of the box with the supplied kit/template or work the door out of the box (yes its possible with some slight trimming of the door, usually 1/4" off the bottom corner opposite the pivot).

NOTHING makes this amount of work worthwhile!!! between this and dropping the exhaust to change the damn o2 sensors, I should have bought a whole new vehicle! Thanks for the tip. what's the story with the blend door then?
 






NOTHING makes this amount of work worthwhile!!! between this and dropping the exhaust to change the damn o2 sensors, I should have bought a whole new vehicle! Thanks for the tip. what's the story with the blend door then?

I know, the serviceability on these things are horrendous. Probably the new cars are even worse. Blend door is a very real problem for our trucks. The top of the blend door is driven by a motor with a D shaped hole at the top. It is made of very cheap plastic. Eventually it breaks and you have either all heat or all cold. Did you ever hear clicks when you adjusted your temp? That is the noise of doom.

Imagine doing the core and having no heat!!
The previous owner may have done it but why take a chance?

If it does break after your repair- you have choices -
1) the same procedure to remove the core, since it is in the same box. NAPA and other stores sell the door, or you can goto ford and get the entire box with a $150+ pricetag.
2) a stopgap measure where you put a pin in the motor shaft, 50/50 chance of working.
3) Putting in the door thru the evap core hole, I did it that way and its tricky/PITA to get the door in.
4) Cutting the bottom of the box and epoxying it back into place.

You can search blend door here if you want more info.People do pull the heater box to fix the door, and will change the core for PM. But having the heater core out is a great time to do the door.

You also have to remove the blend door motor to do this, which will be very easy once the dash is out. Another reason to do it now.
 






96, you've sold me, I guess that blend door's getting added to the list. So do you think that air bag slide contact may have something to do with the column rotating once it's out of the truck and they want it off first so it doesn't matter? As far as I can tell, there was absolutely NO reason to take the wheel or anything else off the column and it could have been pulled in one big piece.
 






96, you've sold me, I guess that blend door's getting added to the list. So do you think that air bag slide contact may have something to do with the column rotating once it's out of the truck and they want it off first so it doesn't matter? As far as I can tell, there was absolutely NO reason to take the wheel or anything else off the column and it could have been pulled in one big piece.

Ask the napa man for: BK660-1810. Its like 11 bucks or so.

All I can say is when you replace a rack you have to be careful not to over rotate the clockspring, so the wheel has to be secured. Maybe they worry you will turn the wheel too much when it is off the car, it may freewheel when disconnected. I don't see any logic in taking off the steering wheel since all the harneses get disconnected under the dash. Unless you are doing work in the column, I dont know why you have to pull the wheel. Anyone disagree?
 






This is getting pretty damn involved! Okay first off, I think I've answered my question on the entire useless tear down of the steering column. Basically, DON'T DO IT! The entire point to complete disassembly seems to be for the sole purpose of protecting the air bag slide contact because if the wheel rotates from the center position it will get damaged. BUT, how about a little footnote saying: be careful, don't rotate the wheel after you pull off the column and then it can simply go back in one piece!

PS, the factory manuals SUCK! I struggled getting the blend door wire connector off, next step told me to reinstall the glove box door. TOO BAD there wasn't a previous step telling me to take it off in the first place, it would have made getting that connector off a 2 second job instead of bending my arm in a pretzel! Also, there's no such thing as "grab the bulkhead connector handle, pull and remove" There's 6 locking tabs on it that would have broke if I'd tried pulling any harder. Go in from the engine compartment, squeeze each set of them and it popped right off. I've got about 5 hours into this so far, (probably two of real work and three staring at it wondering why the hell I'm doing this!)

I came across a bulletin that says you should hose clamp a ground wire to one of the heater core tubes and it will prevent the premature failure of them because apparently these die so quick because the cores aren't grounded in all that plastic they're mounted in.
 






This is getting pretty damn involved! Okay first off, I think I've answered my question on the entire useless tear down of the steering column. Basically, DON'T DO IT! The entire point to complete disassembly seems to be for the sole purpose of protecting the air bag slide contact because if the wheel rotates from the center position it will get damaged. BUT, how about a little footnote saying: be careful, don't rotate the wheel after you pull off the column and then it can simply go back in one piece!

PS, the factory manuals SUCK! I struggled getting the blend door wire connector off, next step told me to reinstall the glove box door. TOO BAD there wasn't a previous step telling me to take it off in the first place, it would have made getting that connector off a 2 second job instead of bending my arm in a pretzel! Also, there's no such thing as "grab the bulkhead connector handle, pull and remove" There's 6 locking tabs on it that would have broke if I'd tried pulling any harder. Go in from the engine compartment, squeeze each set of them and it popped right off. I've got about 5 hours into this so far, (probably two of real work and three staring at it wondering why the hell I'm doing this!)

I came across a bulletin that says you should hose clamp a ground wire to one of the heater core tubes and it will prevent the premature failure of them because apparently these die so quick because the cores aren't grounded in all that plastic they're mounted in.

Yeah, the ground strap is probably a good idea. If you stick a voltmeter (neg terminal) on the neg battery terminal and the pos voltmeter terminal in the coolant and you see over 1 volt there is probably stray electrical currents eating your heater core
 






The fun never ends. Okay, after screwing with one of the nuts on the evap housing for a day (rusted on nut and the whole stud was spinning with no way to grab the other side) anyways, I finally got it off and I get crushed again. There is NO way to pull this evap housing away from the firewall because the metal tube one of the heater hoses connects to completely blocks the housing from moving forward. The pipe is pretty stationary from what I can see of it, I can't even get the rubber hose off of it because the bend is so tight up into the housing. Did I mention I've got a V8 in this piece of junk? Even the factory manuals make no mention of the hose pipe being an issue. Even disconnecting it from the front doesn't look like it will help as it's welded in to some bracket with a second pipe running along side it somewhere up under the aluminum cap on the engine. Now I've got to tear that off too? This is beyond ridiculous. I refuse to time how long I'm spending on this because I'd have probably made out taking it somewhere for the gouging. Before I take the engine apart to get that damn pipe off, anyone have any other ideas here?
 






Those s shaped hoses do come off-there is no need to temove the coolant bypass tubes.
You should replace them anyway-take a razor knife-slice them along the heater core connection. Or-just cut em off.

Also
the ac blower housing splits into 2 parts-this will allow the passenger side of it to move further back.

oh
BTW
there are a couple of heater housing bolts on the firewall that are way in there and a bummer to get to-Are you sure you got all of them?
 






Those s shaped hoses do come off-there is no need to temove the coolant bypass tubes.
You should replace them anyway-take a razor knife-slice them along the heater core connection. Or-just cut em off.

Also
the ac blower housing splits into 2 parts-this will allow the passenger side of it to move further back.

oh
BTW
there are a couple of heater housing bolts on the firewall that are way in there and a bummer to get to-Are you sure you got all of them?

Jon,

There was NO way that evap housing was moving without taking the bypass tubes off. The metal end of the tube overlaps the housing by a good two inches. I ended up taking half the damn motor apart! Air intake's off, coil packs are off. I'm not really understanding the water bypass tubes. I found the bolt holding the back of the tubes down by the egr. After taking that off, I noticed the one tube going into the hex knuckle that has a sensor sticking out of it and screws down into the lower intake moved a little bit. I tried unscrewing that fitting and it didn't really want to budge in that aluminum but the tube came up about an 1/8 inch with some wiggling. How exactly are those two pieces connected? Some kind of O-ring joint or something? With all the horsing on that tube trying to push it back out of the way of the evap housing, I'm not trusting the hose back there anymore either. Can you buy just the gasket for where the air intake mounts to the upper intake or can I get away with some #2 form-a-gasket?

Anyways, even with all that crap off, I was barely able to push the tube back far enough to clear the housing. I'm almost at the point where the box is ready to come off the inside. I can see some vac lines coming through the housing under the blower motor. Ran out of time tonight for the final push to get this thing out. Man, I can't believe how much crap is off the motor right now. I'm really worried about those tubes. I'm sure I can get everything else all back together, maybe I should replace that one heater hose because it may have some cuts in it where it was getting bent over the end of the bypass tube as I was trying to force it out of the way of the housing. Maybe while I'm this far I should change the #1 injector -- I'm still getting a misfire #1 cylinder error code. I have a new maf for it which someone suggested is the problem but never got around to putting it in before the heater core fiasco. Now, who know's if this thing will ever run again! I should have documented the 2 million connectors I had to unplug getting all this crap off! Fought with the PCM nuts all night trying to get them off, everything's rusted on this thing and none of those nuts came off without a struggle and the spinning studs didn't help.

Tomorrow I'll have to skip working on this, it's my anniversary and I doubt she'd be happy with me working in the garage all night!

Later,
Dennis
 






That bypass tube is in very tight. I'm sorry to say but you probably need to get it out now-so you can clean the threads and put some sealer back on there-

It's a PITA to get sealed back up. It might just be me, as the angle is awkward and I have a few problems in my back-
I promise though-I feel your pain

http://www.explorerforum.com/forums/showthread.php?t=173650&highlight=column
 






That bypass tube is in very tight. I'm sorry to say but you probably need to get it out now-so you can clean the threads and put some sealer back on there-

It's a PITA to get sealed back up. It might just be me, as the angle is awkward and I have a few problems in my back-
I promise though-I feel your pain

http://www.explorerforum.com/forums/showthread.php?t=173650&highlight=column


Heater core is FINALLY OUT! now I've got to deal with this bypass tube before trying to put this thing back together. The problem isn't the portion that threads into the manifold, it's the piece that the metal tube goes into at the top where there sensor screws in as well. It's loose now, a lot looser than it seemed at the beginning. As I was turning the fitting back and forth about a tenth of a turn, the top part started coming up off the threaded nut part, at least an 1/8th inch. now I can wiggle it back and forth over the nut that threads into the manifold. What is going on here? It's not like a flare nut on brake lines where the nut turns individually from the line. This thing seems to rotate on the piece threading into the manifold Is there some o-ring junction up inside that's deteriorated and sloppy now? There was WAY too much taken off the motor to get to this point for me to just put it back together now without knowing it won't leak. I've been soaking the nut in WD40 and it seems like it's ready to come out of the manifold but I don't want to try it until I know I really need to take it off and fix something. How do you post pictures on this forum? It looks the same as the GTO forum I'm on all the time but doesn't have the "manage attachments" button to load pictures on the thread.

Thanks,
Dennis
 












Okay, first off, NO it's still not done! While it was apart in the engine compartment, I noticed I was able to actually touch one of the manifold bolts so I decided to tackle part two of my problem and drop the exhaust to repair the pipes where some moron cut the pipes to remove to motor and then did a crap job rewelding them together so I had a bad exhaust leak. So pipes are back on, all the o2 sensors replaced and it's time to put the motor back together. I was pretty pissed when I found that the motor never would have needed to come apart if that metal heater hose tube wasn't all bent to hell which required it's removal to get the evap housing off. I rebent it correctly and now it clears the housing completely! Oh well, my main issue now is that it's been so long I can't remember which hose goes where between the heater core and the metal tubes. I don't think it matters however one of the lines has a shutoff valve on it with an arrow pointing out and I don't really know which direction the flow is from the pipes. Does the tube running from the waterpump connect to the valved hose or does the tube coming up from the manifold with the temp switch connect to the valved hose? I searched this whole site and can't find a picture of a motor!
 



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