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replacing the heater core in an '86 KC Z24i 4x4 ST posted by lostonabackroad:


> Niss4x4 heater and dash <


This isn't a job for the faint of heart...or the chicken mechanic.

*Some advice: don't let chickens work on your truck...and they sure can't drive either!

When I bought this truck...I tested the heater in the middle of summer and noticed the tell-tale smell of antifreeze. Bought the truck anyway...hoping it might be a pinhole that could be closed with stopleak. Not so.

Some advice:

* There are a lot of wires under the dash and a good many fasteners to keep track of. Usually each wire has a connector that can go only one place...but if you are not sure...LABEL THEM. I use plastic sandwich bags and a marker to label the bolts/screws for each part I remove.

* Don't be afraid of removing the's got to go and is really almost the easiest part to remove.


Now to begin:

* Gird your loins...not sure what this involves but it's probably a good idea.

* Remove the negative battery cable.

* I would start with the steering column surround...remove the screws and pull the halves apart.

* Then the instrument cluster comes out...remove the surround and then the cluster...unplugging stuff from the back.

There is also the speedometer cable. This has a plastic snap or catch on it that lifts off the speedometer connector in back....just use fingers to remove it by lifting and flipping it up away from the speedometer connector.

* Then there is the heater control cover...remove the knobs by pulling them off...then remove the cover.

* Then the center console with radio and gauges.

* Next is the dash itself...held on by 9 bolts. 3 on top...4 on the sides...1 in the glove box and 1 down below.

* Then the heater motor....remove the bolts to the back. And the cable and wires.

* Next is the AC box...guess you don't NEED or WANT to remove this...espec if your AC still works...but I did so I could remove the evaporator and clean and seal the box. It acts as a duct from the blower to the heater core.

* Then the heater controls...just let it hang.

* Finally the heater box. Need to remove the hoses first...then the mounting bolts.


I won't go into detail about putting it all back together...but will say that taking it apart is easier.

Getting the core into the heater box and the box closed around it can be fun.

Will say that you DO NOT want to put any strain on the heater core outlets...either when assembling things or when the hoses are put this can cause leaks. DON'T overtighten the hose clamps...but don't undertighten them either.

Adjust and lube the heater controls and all doors in the boxes and make sure they work as easily as possible. The lever that changes things from heat to defrost to vents still was pretty stiff operating after I did everything I could to lube and adjust it.

I cleaned all the boxes and used some new foam tape to seal between the AC and heater boxes.

I pulled the end of the heater motor and put some oil in the bearing...careful of the brushes...also dripped some oil on the fan-end bearing. Careful with the resistor coils.

Got it all back together and it actually works. Controls are real smooth...except for the heat/vent/defrost control...a bit stiff still. Before putting the dash in...I ran the truck up to temp a couple of times...testing the heater controls and checking for any COOLANT LEAKS before going further.

Installing the dash isn't too bad...just takes time to align everything as you go. Instrument cluster is the reverse of removing it.

I also snugged and lubed all electrical connectors under the dash.

It's a mess under there...but somebodies got to do it. At least I know what's under there now...I think.
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