Removal Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Drain the cooling system. Refer to Draining and Filling Cooling System .
Disconnect the heater cord from the coolant heater (4).
Loosen the coolant heater bolt.
Remove the coolant heater from the engine block.
Do not score the machined surface of the hole.
Grasp the plug with pliers.
Pull the plug from the engine block.
Clean the core plug hole in order to remove the following substances:
- Burrs
- Compound
- Paint
- Rough spots
  
  Fig 1: Disconnecting Heater Cord From Coolant Heater
  Courtesy of GENERAL MOTORS CORP.