open the hood.
remove the clamps on the heater hoses going into the firewall.
mark which hose goes where.
pull the hoses off the heater core pipes, and put the ends in the hood hinge facing up.
go into the passenger side of the truck.
open the glove box.
remove the glove box door cable, and the 3 screws holding the door to the dash. remove the glove box.
look straight in, and you will see i believe it is 6 screws. remove those screws.
remove the cover.
remove the heater core.
clean the heater box before you put the new core in, and reverse the steps to assemble.

total time will take 45 min to 1 hour.


notice i did not mention draining the radiator??

you don't need to do that, because the heater core is higher in the truck than the top of the radiator.