This is really not as hard as it would seem to be, or as others make it sound. Just take your time so you don't break anything.
Tools:
Phillips screw driver
Flat head screw driver
1/4" socket
7mm socket
1/4" drive swivel adapter
1/4" drive 6-8" extension
1/4" drive ratchet or handle
Towels
Parts:
New heater core
New heater lines (reccomended)
First step would usually be to dran the radiator about half way. You have to get the fluid level below where the heater line enters the radiator or it's going to make a big mess. My heater core decided to leak right at the begininig of my 37 mile trip home, so it was boiled down that far before I got started, so I go to skip this step. If you need to drain the radiator you'll find the petcock just above the drivers side frame rail on the rear of the radiator. You'll need a large catch pan as it will run onto the frame and go in a couple directions at once.
Once the fluid is low enough you can conect the line going frmo the heater core to the radiator on the radiator end and allow fluid to drain from the hose into your catch pan. In order to minimize the coolant you dump on the floor of your truck I would reccomend either removing the heater hose that goes from the engine to the heater core at the engine, or cutting it at a high point. This will allow you to purge the heater core either with a compressor or yee ol' luings.
With the heater core as dry as you can manage, remove the heater lines from the Heater core. There is a bracket that holds the hard lines of the heater core to the blower box. This has to be removed or the heater core is going no-where. Mine took a 7mm socket to remove an overly long screw, then the bracket just un-clips from the lines.
Now we're reay to move into the cab. There are several things that will be best to be removed to make this as easy as possible. My reccomendations would be to remove the radio(and bezel if you have a single din unit), the plate at the back of the glove-box, the kick pannel, the ECM, the vacum solenoid that controls the vent behind the kick pannel and the glove box door. This all should give just about anyone enough room to get at all 6 screws holding the cover on.
You do not have to remove the dash, but you will need to remove the bolt at the bottom next to the kick pannel and loosen the two screws under the passenger side defroster vent. The dash will need to be shifted a little over an inch to have adequate room to get the cover and the heater core out.
From the radio and glove box you'll need to remove the soft lines connected to the top of the cover, they should just pull off with a little twisting. The part that they hook onto is removeable, but there is not enough room to get it out while the cover is in the dash.
There are six screws holding the cover to the box. Two on the top, two on the bottom and two on the right. The bottom two are easily accessible from under the dash. the rigth two will require a short hex driver up inside the dash from teh bottom, you'll quickly see why we removed the kick pannel and vacum actuator if you have larger arms. The top two are a bit of a chore. The left most one si accessible from behind the radio, it is derectly behind the piece that connects the two soft lines we removed earlier. Looking strain in fromt he radio opening it will be down and to the right. This is where the long extention and swivel adapter comes in. The other upper screw is accessible from the opening in the back of the glovebox, also down and to the right.
One you have these six screws removed I would reccomend removin gor loosening the screw on the main air distrobution unit just next to the left lower screw, this will make it a bit easier to remove the cover.
We're now ready to remove the cover. You'll want to start by pulling the dash away fromt eh firewall about an inch. Next you'll need to reech up under the dash on the right side and pull the cover forward, there is a small tap that will keep the box from moving to the right that you need to pull loose. This will allow the cover to shi8ft to the right about an inch and a half. There is a large foam weatherstripping that wraps around the cover and heater box where it plugs into the main air distrobution housing, this will need to be cut right at the endge of the cover. This may let a tiny ammount of air leak out, but replacin ghte whole thing is infeasable witout removing the whole dash and heater box. The cover should now be loose and will allow you to rotate it around the heater core and remove to the bottom.
there are now two brackets being hel on by four screws that hold the heater core to the box. Both bottom screws are pretty easily accessible from under the dash and the uuper left one from the opening in the glove compartment. The upper rigth is not readily accesible. Your besyt bet is to just remove the three that are and bend the bracket out of the way a bit, ti's fairly sturdy, but don't go crazy on it.
Now you should be able to remove the heater core. You'll start by pulling it back and down slightly till you run into the dash, then you'll have to rotate it counter clockwise about 70 degrees and it should pull the rest of the way out. Some wiggling will be required to get the larger ends of the heater hard lines through the firewall.
congradualtions, you're exactly half way done. The re-install process is just the revers as listed above, with a few small notes. You are more tha likely going to have to bend the hard lines on the heater core a couple of times to get it through the firewall and to line up with the bracket in the engine bay. the copper lines will bend with a little force, but be careful and hold the heater core by the end tanks while bending. Also, be careful with the heater core bracket on the right when re-installing the heater core, it's going to get in the way a tiny bit, just push it out of the way just enough and tyr not to bend it back and forth. if it breaks you're probably going to have to get one from a junk yard or try to fabricate one, not fun.
