GM Service Manual Online
For 1990-2009 cars only

Thermostat Bypass Pipes Replacement 6.6L LLY

Removal Procedure


    Object Number: 1335432  Size: SH
  1. Remove the drive belt. Refer to Drive Belt Replacement for the 6.6L (LLY) engine.
  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 for the 6.6L (LLY) engine.

Installation Procedure


    Object Number: 1335432  Size: SH
  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 drive belt. Refer to Drive Belt Replacement for the 6.6L (LLY) engine.

Thermostat Bypass Pipes Replacement 6.6L LMM

Removal Procedure


    Object Number: 1335432  Size: SH
  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 .

Installation Procedure


    Object Number: 1335432  Size: SH
  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 .