Coolant Heater Replacement 4.3L

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Remove the coolant jacket plug, if not originally equipped with an engine coolant heater, by using the following procedure:

2.1.	Carefully tap the coolant jacket plug near the outer edge. This causes the plug to rotate in the hole.

Do not score the machined surface of the hole.

2.2.	Grasp the plug with pliers and pull the plug out.

3. Remove the cord from the engine coolant heater.
4. Loosen the bolt.



5. Remove the engine coolant heater.
6. Clean the core plug hole. Remove any the following conditions:

•

Burrs

•

Compound

•

Paint

•	Rough spots

1. Apply a coating of lubricant to the O-ring seal and the cleaned surface of the plug opening in the block. Use a water spray resistant, high-temperature grease lubricant (GM P/N 9985164 or equivalent).




Important: Install the heater element. Avoid element contact to the inner walls of the engine block.

2. Install the engine coolant heater and push tight to the block.




Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Tighten the bolt until both locking wings draw tight against the inner wall of the engine block.

Tighten
Tighten the bolt to 1.9 N·m (17 lb in).





Important: The heater cord must not touch the following components:

•	The engine

•	The hot pipes

•	The manifold

•	Any moving components

4. Install the heater cord to the coolant heater.



5. Route the heater cord (2WD).



6. Route the heater cord (4WD).
7. Fill the cooling system. Refer to Cooling System Draining and Filling .
8. Inspect the cooling system for leaks.