Thermostat Bypass Pipes Replacement 6.6L Engine

1. Remove the thermostat housing crossover with the thermostat bypass pipe attached. Refer to Thermostat Housing Crossover Replacement .
2. Remove the thermostat bypass pipe and O-ring seal from the water crossover.
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 crossover.
5. Install the thermostat housing crossover with the thermostat bypass pipe attached. Refer to Thermostat Housing Crossover Replacement .