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Heater Core Swap in a '98


thegoat4

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The worst happened the other night. Driving to HEB, turned on the heat, and POP! Antifreese mist all over the windshield. Crap. I do NOT like having parts of my truck disabled, tied off, or otherwise. Especially when they explode.

The core was $60 at my favorite Ford dealer. They couldn't locate that little foam oval that goes around the pipes at the passthru. I just flipped the old one over.

Needed tools: preferably a screwgun or small impact and an air ratchet for all of the screws. You can do without, but you will not be happy. Air blow gun or hair dryer. Garden hose (with water). Big torx bit, I believe T45, but I might be wrong. Two-jaw puller. Plastic trim clip remover prybar thingy. Pointy object, like an o-ring pick. Flat and phillips screwdrivers. Flashlight. Buddy. Perhaps a copy of the Bible or Zen and Motorcycle Maint.

The procedure is basically what's in the manual, but with some changes to avoid opening the AC system. I also removed extra stuff for more handholds and less confusion.

Unhook battery, remove air bag modules, ignition cylinder, glove box door. Lay the air bags dangerous-side-up; resist the urge to stack other parts on top of them.

Remove trim along bottom edges of doors, and trim from the floor to the leading edges of the door frames. The left side took scary prying of a plastic "nail" below the parking brake. Pry out the piece of trim across the top of the dash, near the windshield.

Pull steering wheel off, remove trim around column, top piece is a pain. Remove the park release and hood release handles, trim below the steering column, and the kneecap catcher shield behind it. Pull center console with the radio still in it, remove trim around cluster, remove cluster. Good time to change those lightbulbs if you need to.

In the engine compartment, the fuse box is held in place with two plastic tabs. Pull it loose and lay aside. You see three plugs with bolts in 'em on the firewall below. Unscrew all three. Pull the heater hoses and plug with bolts if you still have water in the system. Pull off the air intake pipe. Unplug the ECM. Unplug the sensor in the accumulator, take loose the washer hose running over the blower box. There are three studs on the firewall side and one stud back inside the cab you need to remove the nuts from. Look below the glovebox hole and you'll see it on the wall. Once the box is loose, roll it away from the firewall over the top of the engine and hold it back with a bungie cord. Mind kinked hoses.

Back inside, unplug everything you see. You don't need to, but unplugging everything is faster that figuring out what's what. There will be a ground lead on the passenger side, near the door frame. Here's the worst part of all. Those three plugs you unscrewed on the firewall, they plugged into a big honkin' plug monster on the cab side. It has six hellish little plastic clips. Good luck. I pulled back on the plug gently and pried each tab with a pick one-by-one in the dark by feel at a funny angle while more or less applying a sleeper hold to myself. While you're there, unplug the pedal switches and steering column. Remove the column, it has a pinch bolt at the u-joint. Try not to rotate the shaft after removing.

I took out the AC controls, but it seemed like I didn't need to.

There are two little screws towards the middle of the dash, against the windshield. Remove. There is a brace left of center at the bottom near the ashtray. Remove. Get a buddy. Take out the big bolts you see along the windshield and door frames. Pull the dash back a bit. There's a big plug on the left, screwed together with a 10mm head. Have a ratchet ready and unhook it. You could reach it through the cluster hole before puling the dash, but it kinda sucks.

There are random wires with those stupid plastic clips/nails holding them to the dash. You'll need to pry a couple loose. Be careful with the antenna wire one as it's more sensitive to abuse. I've got one on order. Put dash somewhere clean, not like I did. I blame the brainular blood starvation brought on by that plug monster.

Heater box has four studs going through the firewall. Three near the blower box, one near the center of the wall. Remove the heater box, take off the cover of the heater core, pull off the oval foam piece, and just cut little slits in the other foam piece, slide out the core. Now go hose out all the damned antifreeze, barsleak, bugs, M&Ms, and whatever else has accumulated in that box. Get it clean as you can and make sure to blow all the water out of the foam. Hair dryer for those without compressed air handy.

Doesn't the truck look weird without the dash in it? Yeah, I thought so. This is a good time to change your registration sticker. You can get ALL of the glue off.

Now, put everything back together. It's pretty self-explanatory at this point. The only trick is leftover screws. I had three. One was kinda big. Hmm. Don't forget that screw-together plug on the left before you hang the dash back up, and the center brace at the bottom of the dash. Each time you're about to cover up a hole, take a good long look inside for screwless holes and bachelor plugs.

Plugmonster is much nicer on reassembly. I snapped off four of the tabs for the sake of my future self.

Torque guidelines: little screws, studs, and bolts-snug. Plug screws-snug. Other ones-tight.

Top off or fill the coolant, check all of your fuses and lights, wipe off the 800 handprints on the dash, and the two footprints on the ceiling. Turn up the heat full blast and run the truck up to temp, top off the surge tank.

Commence happydance.

I made close to a dollar on recovered change!
 


Rock Auto 5% Discount Code: 7FA902352B4C01: April 5th, 2021

RobbieD

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My credo
Toonces drives a Ranger . . . . just not very well.
Good write-up.

I'm sorry guys; the newer trucks sure do look nice and everything, but I'll have to stick with my older RBVs for the "less PITA" factor on repairing them.
 

98greenrangerguy

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Wow, I hope I never have to go through that. Changing the damned spark plugs is a big enough headache.
 

Jim Oaks

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Thanks! I'm adding it to the magazine, but I wish there were some pics to go with it. I'll have to find a pic just for linking off the magazine index.
 

rangerrunner

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Heater core pics

It just so happened that I had to go through this over the weekend. I found the writeup VERY helpful (along with alldatadiy online!) This job brings to mind a few choice words. Nightmare and hellish are a couple of mild ones!!! Anyway, I got it done and I appreciate the advice, especially about not purging the A/C. I did put the camera on the workbench and recorded a few of the "highlights".


After pulling the steering column I laid the dash on the seats. The only thing I did not disconnect was the antenna wire.


I did neatly lay the parts safely out of the way.


Those air bags got their own spot even further out of the way!


When you get all the inner plenum bolts off it practically falls off the firewall.


I left the A/C charged and pulled back the evaporator core housing just enough to reach the fasteners.


Just pull that bad boy out...


...match up, test, attach some padding and drop that new baby in.

Thank god its over!!!
 

almostclueless

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This is one of my biggest gripes to the engineers....



Why they couldn't F'n make the heater core as easy to replace as the 80's rangers!!!!!
 

colinrmitchell

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Oh Christ. :fie:

I have to do all that?

I think I'll just plug an electric heater into my power inverter! :icon_thumby:
 

colinrmitchell

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1997 Ranger Heater Pictures.

Well, I just got done fixing my heat in my 1997 2.3L today. I took a few pictures to supplement the literature posted above. My heat randomly and suddenly went out on me sometime in October. It's been a cold winter so far!

This is my first time working on heaters, but here's a few things that may supplement a straight-forward heater core swap.

First, I made sure to track down all electrical and vacuum connections after I lowered the dashboard, to make sure that it was nothing mechanical or electrical. When I messed around with my intake earlier in the season, I may have accidentally disconnected the vacuum supply for the coolant valve for the heater core. This was located by the header on my 2.3L (passenger side probably, on others). It's grey with a black 90deg. boot on the end, and it plugs into the bottom of the vacuum valve. Gotta have this to even get heat in the heater case.

Also, the different vents are operated by vacuum connections. There's two behind the dash, just to the left of the radio. These work the vent/defrost and floor, respectively. There's also one behind the glove compartment that operates the in-cab air recirculation. If you open the glovebox and lower it down (with the dash installed), you can see a rubbery, transparent blue connector and a white socket, that connects the vacuum tubes from the firewall/heater box to the dash. These allow you to switch where the air/heat comes from.





I replaced the heater core in my truck, but that didn't turn out to be the problem. What may be the problem (and maybe you should check before ordering a new heater core, just in case) is if the blend door is functioning properly. There is a white case that houses a motor and some gears, that operates the blend door according to the blend fader on the dashboard. A "key" comes out of the bottom, and connects into a socket in the blend door, where it swivels to control the levels of heated and unheated air entering the cab. My "socket" was broken, and the motor would turn, but would slip through the socket and not turn the door, and my blend door was left stuck in all-cool mode. Mine was pretty broken, would've taken a while to try to fix, so I just glued the door in the all-hot position, since I only use the air system for heat.

To aid the above narration, here's a picture of "plugmonster" from the engine bay:



The in-dash heater case is held on with four bolts. Two are on the blower-motor case in the engine bay. These have double-nuts: there's a nut, then the plastic blower motor case, then another nut, then the firewall. Make sure to take both of these bolts off! It took me a while to figure that out! :blush: There is another bolt in the very center of the firewall, just behind the engine block. It was a big pain to get to. There is also one in the passenger compartment, under the dashboard.



When you reinstall the dash, lower the glove compartment all the way, and make sure the blue vacuum plug and the connector for the blend door motor are installed. It wouldn't hurt to recheck the coolant vacuum valve in the engine bay one more time, since it may get knocked out while messing with bolts.

I hope this helps a little. Wish I would've known this sooner before I blew $60 on a brand new heater core!!

Regards,
Colin.
 

almostclueless

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My heat randomly and suddenly went out on me sometime in October.

Wish I would've known this sooner before I blew $60 on a brand new heater core!!

Um, a heater core RARELY just stops supplying heat. If you asked we could have told you that. MAYBE if it COMPLETELY stopped up with coolant system sealer, but that would take a lot of sealer.


People almost always change the heater core because it's responsible for a gallon of antifreeze in the floorboards....
 

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My heater stopped sending out hot air. The blower works and there's no fluid on the floor. I had a new engine put in with all new hoses. I unhooked the vacuum line that's hooked up to one of the hoses that goes to the heater and the hot air came back on. Then it stopped again. I tried the same trick but no hot air. How do you check the blend door adjustment gears?

1999 Ford Ranger

Um, a heater core RARELY just stops supplying heat. If you asked we could have told you that. MAYBE if it COMPLETELY stopped up with coolant system sealer, but that would take a lot of sealer.


People almost always change the heater core because it's responsible for a gallon of antifreeze in the floorboards....
 

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four-d-ranger

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UPDATE! Here's how to avoid giving yourself a self applied sleeper hold!

Thanks for posting this TheGoat4, This article helped me so much (I had to do it while my back was thrown out, yikes!) that I had to share what I learned.

Regarding removing the large driver's side electrical plug from the inside firewall-After having applied a sleeper hold to myself and finally managing to get all six clips released at the same time, I realized that there's a black trim ring about a half inch wide, installed around the plug from the engine bay side. Simply pull that trim ring off and all six clips are easily accesible from the engine bay and the plug literally falls through the firewall.
 

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ARE u kiddin!!! REPLACE HEATER CORE

:icon_twisted:
WOW WHAT A MAJOR PAIN IN ASS, I NEED TO REPLACE MY HEATER CORE
ON MY 98 RANGER, WTF DONT THEY MAKE IT EASIER?:icon_hornsup:
IF U HAVE ANY TIPS PLEASE LET ME KNOW
BESIDES LOTS OF DOWNERS!
 


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