Removal Procedure

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: View Of Coolant Heater (4.3L)

Courtesy of GENERAL MOTORS CORP.

Drain the cooling system. Refer to Cooling System Draining and Filling (Static Fill) or Cooling System Draining and Filling (Vac-N-Fill) .
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