How do you replace the heater core in a 1993 Toyota pick up 22r?

You'll have to drain your coolant and disconnect the two coolant hoses that go to your heater core at the firewall. Remove the 2 bolts you see between the hoses on the firewall. Inside, you'll have to remove you entire dash. The support bar that runs from door to door needs to be removed. From here, the linkage from the controls needs to be removed, the screws securing the heater core housing to the rest of the ducting and A/C core need to be removed. There are a number of nuts that must be removed at the inner firewall as well. The heater core housing is 2 piece. Unscrew the retainer screws and separate the 2 halfs to expose the core. Good luck!