Removal Procedure

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. 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 .
Raise and support the vehicle. Refer to LIFTING AND JACKING THE VEHICLE in General Information.
Disconnect the coolant heater cord from the coolant heater.
Loosen the bolt at the coolant heater but DO NOT remove the coolant heater bolt.
Remove the coolant heater.

Fig 1: Removing Coolant Heater (3.8L)
Courtesy of GENERAL MOTORS CORP.
Remove and clean any burrs, compound, paint, or rough spots from the core plug hole.