I've done a couple S-10 heater cores and they're not the easiest but they're also not as bad as, say, a 1996 Mercury Sable which requires the disassembly of the entire car.

Make sure you remove all the screws and bolts holding the dash to the firewall. You'll need those extra couple of inches to take the screws out of the heater core case. Be careful and patient; take your time. It will come out.

 

The person that owned my '94 blazer before me did this. Twice. He said he did it with the dash in-tact both times, and that it wasn't that bad.

I've done one on the newer trailblazer, in which you have to remove the entire dash. Even that I would only put on a 6/10 difficulty scale. It seems really scary, but a few bolts and some careful movement of the dashboard makes it come out pretty easily.

 

I also did the heater core in mine last year. I removed a few of the bolts on the dash like a write up had said. I would say the most difficult part is getting it back into the right spot exactly so the 2 clips screw back in properly. Otherwise it was pretty easy. DO! remove the radio and the access panel in the glove box. This does help and the little vent on top.

I had previously gutted all the A/C parts, so after I removed that and then replaced the heater core and removed all the leaves in there it now blows like a champ too.

 

i wish all cars had access panels like that. i just did a heater core in a 94 c1500 pick up truck. wow. insanely easy. theres like 4 screws holding the cover up. remove cover and the heatercore is sitting right there held in by one more screw. just disconnect the hoses and it comes right out.

 

thanks for the input guys, Im kinda scared to take off the dash but im guessing it should'nt be that hard.

 

Take the dash off and save yourself the trouble, I had to on my 94 blazer. I am guessing there is a reason the guy had to replace the heater core twice without removing the dash and it is probably because he messed it up forcing it in there. And I also agree that it seems sometimes manufacturers arent thinking when designing a car and they make stuff that should be so easy to do next to impossible. A few examples on our blazers would be the heater core and the the O2 sensor?

 

Update!!!!!!!!

well i finally replaced my heater core, it took me about 4 hours to do everything.

It actually went really smooth thanks to the detailed write up that i followed, and to the helpful tips from everyone. Thanks once again for the help. Total cost was about $30, it saved me alot of money.

 

Congratulations! It's always a good feeling when you fix something on your Blazer.

 

Did this a couple (maybe more) years ago. It def. helps unbolting the dash and moving it a bit out.