How do you change the heater core in a 1986 Chevrolet Caprice Classic?

Its actually pretty easy. The heater core is located under the hood, passenger side. Disconnect the two hoses running into the firewall. Remove the leaf guard then start pulling bolts on the black housing. (remember where they go of course, I had 3 different sizes on mine to boot!)You will need to disconnect the wiring harness on the top pf the housing and remove the blower fan before removing the housing. Once you have undone about 25 bolts you can remove the housing. If you have Air Conditioning you will see two "radiator looking things" one of them is your AC Condensor the other one is your heater core. Check a manual to be sure which one. (In my 77 Caprice the heater core was the one closer to the middle of the firewall) If you don't have AC then you should only see one "radiator looking things" that's the heater core, it should just slide out of its little home and you can then put it all back together.