Thermostat Bypass Pipes Replacement 6.6L (LB7) Engine

1. Remove the thermostat housing. Refer to Thermostat Housing Crossover Replacement .
2. Remove the thermostat bypass pipe and O-ring seal from the thermostat housing.
3. Remove and discard the O-ring seal.
4. Clean the sealing surfaces of the bypass pipe.
5. Clean the water pump and the thermostat housing crossover sealing surfaces.

1. Install a new O-ring seal on the thermostat bypass pipe.
2. Lightly lubricate the O-ring seal with coolant.
3. Install a new O-ring seal for the bypass pipe to the water pump.
4. Install the bypass pipe in the thermostat housing.
5. Install the thermostat housing. Refer to Thermostat Housing Crossover Replacement .

Thermostat Bypass Pipes Replacement 6.6L (LLY)

1. Remove the thermostat housing. Refer to Thermostat Housing Crossover Replacement .
2. Remove the bypass pipe from the thermostat housing.
3. Remove and discard the O-ring seals from the bypass pipe and the water pump.
4. Clean the sealing surfaces of the bypass pipe.
5. If required, clean and inspect the bypass pipe and thermostat housing. Refer to Engine Coolant Thermostat Housing Cleaning and Inspection in Engine Mechanical - 6.6L (LLY).

1. Install a NEW O-ring seal onto the bypass pipe.
2. Install a NEW O-ring seal to the water pump.
3. Lubricate the O-ring seals with clean engine coolant.
4. Install the bypass pipe into the thermostat housing.
5. Install the thermostat housing. Refer to Thermostat Housing Crossover Replacement .