GM Service Manual Online
For 1990-2009 cars only

Heater Water Bypass Valve Replacement Standard

Removal Procedure

Tools Required

J 38185 Hose Clamp Pliers

  1. Remove the air cleaner. Refer to Air Cleaner Assembly Replacement in Engine Controls.

  2. Object Number: 280258  Size: SH
  3. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  4. Use the J 38185 tool in order to remove the hose clamps from the outlet pipe (6) and from the inlet pipe (5).
  5. Remove the heater inlet pipe (5) and the outlet pipe (6) from the bypass valves (4).
  6. Remove the bolts (3) that retain the valves (4) to the heater assembly.
  7. Remove the bypass valves (4) from the heater assembly.

Installation Procedure


    Object Number: 280258  Size: SH
  1. Install the bypass valves (4) to the heater assembly.
  2. 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. Install the bolts (3) that retain the valves (4) to the heater assembly.
  4. Tighten
    Tighten the bolts that retain the valves to 4 N·m (35 lb in).

  5. Install the heater inlet pipe (5) and the outlet pipe (6) to the bypass valves.
  6. Use the J 38185 tool in order to install the hose clamps from the outlet pipe (6) and from the inlet pipe (5).
  7. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  8. Ensure that no leaks exist in the cooling system.
  9. Install the air cleaner. Refer to Air Cleaner Assembly Replacement in Engine Controls.

Heater Water Bypass Valve Replacement RPO C36

Removal Procedure

Tools Required

J 38185 Hose Clamp Pliers

  1. Remove the air cleaner. Refer to Air Cleaner Assembly Replacement in Engine Controls.

  2. Object Number: 280257  Size: SH
  3. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  4. Remove the hose clamps from the outlet pipe (6) and from the inlet pipe (5).
  5. Use the J 38185 tool in order to remove the hose clamps from the outlet pipe (6) and from the inlet pipe (5).
  6. Remove the bolts (3) that retain the valves to the heater assembly.
  7. Remove the bypass valves (4) from the heater assembly.
  8. Remove the heater hoses from the engine to the water bypass valve. Refer to Heater Water Bypass Valve Replacement .

Installation Procedure

  1. Install the heater hoses to the engine to the water bypass valve. Refer to Heater Water Bypass Valve Replacement .

  2. Object Number: 280257  Size: SH
  3. Install the bypass valves (4) to the heater assembly.
  4. 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.

  5. Install the bolts (3) that retain the valves (4) to the heater assembly.
  6. Tighten
    Tighten the bolts that retain the valves to 4 N·m (35 lb in).

  7. Install the heater inlet pipe (5) and the outlet pipe (6) to the bypass valves.
  8. Use the J 38185 tool in order to install the hose clamps from the outlet pipe (6) and from the inlet pipe (5).
  9. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  10. Ensure that no leaks exist in the cooling system.
  11. Install the air cleaner. Refer to Air Cleaner Assembly Replacement in Engine Controls.