I just bought an 89 blazer with basically nothing wrong with it (Except it needs a heater core, which was offset in price/time by the free set of studded snow tires mounted on rims...)

As far as i can tell....

SyTyArchives.com - Heater Core

Is a fairly accurate and easy way to do this. Wish me luck, going to attempt today! But if anyone has any sage advice for a new guy, please pass on some sweet sweet knowledge.

Also, i wasn't sure where to post this...

 

Remove the Radio to access the Air conditioning hose at the top of the heater cor box. A little twist and a pull the hose will come out of the top of the heater core cover. If you do not remove the hose first and try to remove the heater box cover you will crack the housing. I know this from first hand experience. Installing the new heater core is a pain because you have to rotate the heater core to get it in the correct position, but the tube openings in the firewall makes it difficult to put the tubes in through the firewall while the heater core is rotated and you chance cracking a solder joint getting the heater core rotated into the correct position. Remove the glove box door and the rear access cover to access some of the cover bolts. You will be able to access all the heater cover bolts from the radio openng, the rear access cover in the glove box and from underneath the dash. Good Luck. In my 89 Jimmy (Original Owner) with about 450K on the odometer I have done the heater core 4 times in the life of the vehical.

 

Replacement was successful. Heat works and no coolant (As far as i can tell) is leaking anywhere. Didn't even have to drain the block as the guy i bought it from had bypassed the heater core entirely. It was one of the most frustrating things i've ever done on a car though....

And for reference, if anyone needs to do it (And has no clue as i did) the instructions in the link in my original post were dead on accurate and easy to follow. Whole job took about 2.5 hours (I assume to my inexperience), and cost 30 bucks.

 

Really good actually considering they give you 4 hours to do it.

 

Yeah, I don't know why they say it's supposed to take that long... Maybe that is factoring in beer drinking...