Ford Ranger Maintaince And Repair Manual page 672

HOW TO USE THIS BOOK
... and allow the cover to drop down. If necessary, you can remove the cover if it is in your way
Remove the heater core access panel attaching screws ...
... then remove the cover by pulling downward and straight back to disengage the drain tube
(arrow)
4. Pull the heater core rearward and down, removing it from the plenum assembly.
REMOVAL & INSTALLATION 675