I changed out my NAPA Heater Core for the OEM it replaced 3 years ago.
You don't need many tools: Flat/Phillips screwdrivers (MED), 7mm deep socket, 7/16" deep socket, 9/16" socket, long extension (Taller than seat height), socket ratchet, headlamp.
I tore my liner behind the heater plenum, so I repaired it by using spray adhesive. I also used a hammer to bump the plenum bolts (3) from the firewall side.
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Essentially:
1. Remove back battery and passenger seat (6 bolts 9/16").
2. Remove heater hose at top HC Tube at firewall, and then the bottom one. Prop up so you don't lose coolant (See pictures).
3. Remove 4 screws (Phillips #2) from glove box (TM says "instrument console") Pull glove box out.
4. Remove 2 screws from cable ends on plenum- see picture (7mm). Pry cable end 'loops' off of posts- may have spring nut keepers.
5. Remove 3 nuts from engine bay side (1, 2 & 3 in picture). Two are on blower flange, #2 is to the right as pictured. 7/16" open or deep socket and various extension or configuration wrenches. Be careful not to stress the fuel filter tubes.
All battery cables should be removed.
6. Carefully tap #2 bolt with hammer and extension to dislodge plenum.
7. Work carefully here to avoid tearing the floorboard liner behind the plenum. FIRST pull the plenum straight back until the bolts that pass through the firewall completely clear the liner. Then pull the plenum down and free of the glove box frame. If you tear the liner, use a little spray adhesive to press it back down into place.
8. The HC seal should come out with the HC. If not, remove it now (See Picture).
9. Compare heater core top the one you are replacing. The ones pictured are correct depth. Some will have a 'skinny' body allowing air to flow around them, and you will not get much heated air. Yours may come with foam blocks to place on either side- forcing air through properly. Secure them by threading mechanics wire through the block and twist the ends to secure them to the Heater Core.
NOTE* Force air (Blow) through either side of the HC to be sure there is no blockage BEFORE securing it to the plenum. There are two brackets to secure the HC to the plenum.
10. Replace the seal- a new one is preferred. Replace the plenum; carefully guiding the #2 bolt through the liner and firewall. Rotate into position and replace the nuts (3) on the firewall side.
The rest is just the reverse of this removal.
The last part was to assure that there is no air in the heater hose or heater core: After securing the top and bottom heater hose, AND with the radiator completely topped-off, remove the heater hose from the offset fitting above the passenger-side alternator. Hold your thumb over the fitting. Coolant will flow from the radiator through the HC pushing any air out of the hose. Reconnect, tighten and check for leaks. If you don't bleed the air out your water pump may squeal.
I've done this twice now. It's not very hard- well under an hour if you have all tools in place. You should definitely remove the battery and the seat. Each part takes only a few minutes, and will save you time and frustration.
I like your field repairs as well!! ![[thumbzup]](https://www.steelsoldiers.com/images/smilies/icon_smile_thumzup.gif "Thumbs Up [thumbzup]"){kind=icon}
