GM Service Manual Online
For 1990-2009 cars only

Water Outlet Replacement LY7, LLT

Removal Procedure

  1. Partially drain the cooling system. Refer to Cooling System Draining and Filling.
  2. For the LLT engine, remove the throttle body. Refer to Throttle Body Assembly Replacement.
  3. Remove the radiator hose from the water outlet. Refer to Radiator Inlet Hose Replacement.

  4. Object Number: 902875  Size: SH
  5. Remove the water outlet housing bolts.
  6. Remove the water outlet.
  7. Remove and discard the water outlet seals.
  8. Clean the water outlet housing sealing surfaces.

Installation Procedure


    Object Number: 902875  Size: SH
  1. Install NEW water outlet housing seals.
  2. Install the water outlet.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the water outlet bolts and tighten to 10 N·m(89 lb in)..
  5. Install the radiator hose to the water outlet. Refer to Radiator Inlet Hose Replacement.
  6. For the LLT engine, install the throttle body. Refer to Throttle Body Assembly Replacement.
  7. Fill the cooling system. Refer to Cooling System Draining and Filling.

Water Outlet Replacement LH2

Removal Procedure


    Object Number: 927998  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling.
  2. Remove the throttle body. Refer to Throttle Body Assembly Replacement.

  3. Object Number: 1234885  Size: SH
  4. Remove the manifold absolute pressure (MAP) sensor (3). Refer to Manifold Absolute Pressure Sensor Replacement.
  5. Disconnect the evaporative emission (EVAP) canister purge solenoid valve hose and electrical connector. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement.

  6. Object Number: 1285939  Size: SH
  7. Compress the clamps and remove the following hoses from the thermostat and the water housing:
  8. • The heater inlet hose (1)
    • The radiator inlet hose (2)
    • The heater outlet hose (3)
    • The bypass hose (4)
    • The surge tank inlet hose

    Object Number: 1234875  Size: SH
  9. Loosen the intake manifold duct clamp (1).

  10. Object Number: 1286421  Size: SH
  11. Remove the bolts (1, 2) securing the water outlet housing to the cylinder heads.
  12. Remove the water outlet housing from the vehicle.
  13. Discard the water outlet housing gaskets.
  14. Clean and inspect the water outlet housing. Refer to Water Outlet Housing Cleaning and Inspection.
  15. Remove the following components from the water outlet housing if replacement is necessary:
  16. • The intake manifold inlet duct and clamp
    • The surge tank inlet hose fitting
    • The heater inlet hose fitting
    • The evaporative emission (EVAP) canister purge solenoid valve--Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement.

Installation Procedure

    Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1286421  Size: SH
  1. Install the following components to the water outlet housing if previously removed:
  2. • The intake manifold inlet duct and clamp and tighten to 6 N·m (53 lb in).
    • The surge tank inlet hose fitting and tighten to 18 N·m (13 lb ft).
    • The heater inlet hose fitting and tighten to 20 N·m (15 lb ft).
    • The (EVAP) canister purge solenoid valve and tighten to 12 N·m (106 lb in).
  3. Install NEW water outlet housing gaskets.
  4. Note: The water outlet housing uses two different size bolts. Bolt (2) is approximately 10 mm longer than the other 3 bolts (1).

  5. Install the water outlet housing to the vehicle.
  6. Install the water outlet housing bolts and tighten to 25 N·m (18 lb ft).

  7. Object Number: 1234875  Size: SH
  8. Install the intake manifold duct clamp (1) and tighten to 6 N·m (53 lb in).

  9. Object Number: 1285939  Size: SH
  10. Compress the clamps and install the following hoses to the thermostat and the water housing:
  11. • The heater inlet hose (1)
    • The radiator inlet hose (2)
    • The heater outlet hose (3)
    • The bypass hose (4)
    • The surge tank inlet hose

    Object Number: 1234885  Size: SH
  12. Connect the evaporative emission (EVAP) canister purge solenoid valve hose and electrical connector. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement.
  13. Install the manifold absolute pressure (MAP) sensor (3). Refer to Manifold Absolute Pressure Sensor Replacement.

  14. Object Number: 927998  Size: SH
  15. Install the throttle body. Refer to Throttle Body Assembly Replacement.
  16. Fill the cooling system. Refer to Cooling System Draining and Filling.