GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1999 🢒 Eighty Eight 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Engine Coolant Temperature Sensor Replacement

Notice: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

Removal Procedure

Important: Care must be taken when handling engine coolant temperature sensor. Damage to the engine coolant temperature sensor will affect proper operation of the fuel injection system.


    Object Number: 377745 Size: SH
  1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. Drain the radiator coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.
  4. Disconnect the ECT sensor electrical connector (1) from the ECT sensor (3).
  5. Remove the ECT sensor shield (2) from around the ECT sensor.
  6. Remove the ECT sensor from the engine.

Installation Procedure

Important: Care must be taken when handling engine coolant temperature sensor. Damage to the engine coolant temperature sensor will affect proper operation of the fuel injection system.

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.

Tighten
Tighten the ECT sensor to 25 N·m (18 lb ft).


    Object Number: 377745 Size: SH
  1. Hand start the ECT sensor (3) into the engine.

    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.

    Tighten
    Tighten the ECT to 25 N·m (18 lb ft).

  2. Connect the ECT sensor shield (2) from around the ECT sensor.
  3. Connect the electrical connector (1) to the ECT sensor (3).
  4. Refill the radiator with coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  5. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  6. Start the engine.
  7. Check for coolant leaks.
  8. Check the coolant level.
  9. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.