For 1990-2009 cars

## Coolant Heater Replacement LG5

### Removal Procedure

1. Drain the coolant. Refer to Cooling System Draining and Filling .
2. Remove the heat shield, if equipped.
3. Disconnect the electrical cord connector from the engine coolant heater.
4. Loosen the center screw to the limit of the thread.
5. Remove the engine coolant heater from the engine block.
6. Inspect the hole in the block for smoothness. Remove any burrs or rough spots.

Caution: A block heater electrical cord that is damaged creates a shock hazard, and must be replaced.

7. Inspect the electrical cord and the cord ends for corrosion or damage.
8. Clean the hole in the block.
9. Clean the electrical connectors.

### Installation Procedure

1. Apply a coat of petroleum jelly to the following components:

• | The opening of the heater

• | The rubber O-ring seal

2. Insert the engine coolant heater into the hole in the engine block.
3. Position the hairpin end of the engine coolant heater straight up.

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.

4. Tighten the engine coolant heater center screw.

Tighten
Tighten the engine coolant heater center screw to 3 N·m (23 lb in).

5. Install the heat shield, if equipped.

Tighten
Tighten the heat shield bolt to 12 N·m (106 lb in).

Important: Route the electrical cord so that the cord does not touch the engine, the exhaust manifold or any moving parts. Leave slack between the engine and the frame so that engine vibration will not stretch the cord or damage the connection at the heater.

6. Connect the electrical cord connector to the engine coolant heater.
7. Fill the cooling system. Refer to Cooling System Draining and Filling .
8. Inspect the system for leaks.

## Coolant Heater Replacement L18

### Removal Procedure

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Disconnect the heater cord from the coolant heater.
3. Remove the engine coolant heater from the engine block.

### Installation Procedure

1. Coat the O-ring seal and the cleaned surface of the plug opening with water resistant high-temperature grease lubricant GM P/N 12346004 or the equivalent.

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.

2. Install the coolant heater.

Tighten
Tighten the engine coolant heater to 50 N·m (40 lb ft).

3. Connect the heater cord to the coolant heater.
4. Fill the cooling system. Refer to Cooling System Draining and Filling .