GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 Savana 🢒 Engine 🢒 Engine Cooling 🢒 Thermostat Housing Crossover Replacement

Removal Procedure

    Object Number: 105205 Size: SH

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the battery negative cable. Refer to Battery Cable Replacement in Engine Electrical.

    2. Object Number: 105191 Size: SH
  2. Disconnect the battery negative cable from the auxiliary battery terminal. Refer to Battery Cable Replacement in Engine Electrical.
  3. Drain the coolant from the radiator. Refer to Cooling System Draining and Filling .

    4. Object Number: 183478 Size: SH
  4. Remove the air cleaner assembly from the vehicle. Refer to Air Cleaner Assembly Replacement in Engine Controls.

    5. Object Number: 175681 Size: SH
  5. Remove the air intake duct from the turbocharger.
  6. Remove the nut securing the dipstick tubes at the thermostat housing.
  7. Remove the stud securing the fuel bleed valve at the thermostat housing.
  8. Remove the A/C compressor. Refer to Air Conditioning Compressor Replacement in HVAC.
  9. Disconnect the coolant temperature sensor electrical connector.
  10. Disconnect the heater hose at the thermostat housing crossover.

    11. Object Number: 332048 Size: SH
  11. Disconnect the by-pass hose at the thermostat housing crossover.

    12. Object Number: 160863 Size: SH
  12. Disconnect the upper radiator hose at the thermostat housing crossover.

    13. Object Number: 66572 Size: SH
  13. Remove the studs and bolts securing the thermostat housing crossover to the engine.
  14. Remove the thermostat housing crossover.
  15. Clean the thermostat housing crossover sealing surfaces.

Installation Procedure
  1. Install the new gaskets.
  2. Install the thermostat housing crossover.

    3. Object Number: 66572 Size: SH

    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 studs and bolts retaining the thermostat housing crossover to the engine.

    4. Tighten
    Tighten the bolts and studs to 47 N·m (35 lb ft).


    Object Number: 160863 Size: SH
  4. Connect the upper radiator hose to the thermostat housing crossover.

    5. Object Number: 332048 Size: SH
  5. Connect the by-pass hose to the thermostat housing crossover.
  6. Connect the heater hose to the thermostat housing crossover.
  7. Connect the electrical connector to the coolant temperature sensor.
  8. Install the A/C compressor. Refer to Air Conditioning Compressor Replacement in HVAC.
  9. Install the stud in order to secure the fuel bleed valve at the thermostat housing.
  10. Install the nut in order to secure the dipstick tubes at the thermostat housing.

    11. Object Number: 105191 Size: SH
  11. Connect the battery negative cable to the auxiliary battery terminal. Refer to Battery Cable Replacement in Engine Electrical.

    12. Object Number: 105205 Size: SH

  12. Connect the battery negative cable to the battery terminal. Refer to Battery Cable Replacement in Engine Electrical.

  13. Refill the engine cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  14. Bleed the air from the engine cooling system by the following:
    15. 14.1. Remove the cap from the surge tank.
    14.2. Remove the bleed screw (slotted) from the top of the thermostat housing.
    14.3. Pour anti-freeze into the surge tank, and watch for a of anti-freeze from the bleed screw.
    14.4. When a constant flow of anti-freeze is reached, closed the bleed screw at the top of the thermostat housing.
    14.5. Continue to fill the surge tank to the proper level.
    14.6. Install the cap on the surge tank.

    Object Number: 175681 Size: SH
  15. Install the air intake duct to the turbocharger.

    16. Object Number: 183478 Size: SH
  16. Install the air cleaner assembly in the vehicle. Refer to Air Cleaner Assembly Replacement in Engine Controls.
  17. Inspect the system for coolant leaks.