- 1). Allow the engine to cool for three to five hours before you work on the coolant system. Pop the hood. Put a drain pan underneath the heater core. Remove the hose clamps to the lines running to the heater core with the pliers or a flat-head screwdriver, depending on the types of clamps that secure the hoses.
- 2). Unbolt the rear retaining screws from the heater core, using the 3/8-inch ratchet and socket. Then unbolt the heater core retaining straps from the heater core with the ratchet.
- 3). Pull the heater core assembly out of the heater core panel and set it to the side.