I finally put the new heater core in my 92 Z. Hope never to have to do that again. I’ve been reading threads on 1990 and back on how it’s not much fun but just an hour or so and it’s over. The 92 has to be made different. The top screws on the plastic heater box that covers the core CAN NOT be accessed until the ducting is out of the way and that can’t happen till the dash is removed. In all I removed the seats, console, dash and dash pad, dropped the steering column, and all the ducting. After all that the angle on the tubes on the new core (Napa) were slightly off to the driver’s side compared to the old one making the reinstallation of the premade heater hose (which is no longer available) an absolute nightmare. No matter how we tried it hit hard on the wiring harness. Hours of massaging the core tubes and working the harness over as far as possible we got it in. It took about 14 hours of tedious attention to all those fragile plastic pieces. At the end the only broken piece was the retainer for the core, easy fix. I believe this job was made more difficult because we have never been this deep into a dash before and not knowing what to expect we spent a lot of time looking and talking on what should come out next and how to get it out, never thinking we had to completely remove the dash. This a two person job who have PATIENCE. We also held off on the cold ones till we were done. I have gotten tons of great info from this forum and I hope this helps someone. I have pics but haven't figured out how to put them in yet.

 

Glad you got it done at least. Things like this kinda makes you wonder if cars aren't designed with future service costs in mind, doesn't it? I removed the core and put the ducting back together in my 69, and it took about a half hour. Granted, there's less crap in the way, but you'd think the car manufacturers could plan ahead sometimes.