GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1997 🢒 GMC P42 Commercial Chassis 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Coolant Temperature Sensor Replacement

Removal Procedure

    Caution: Do not remove the radiator cap while the cooling system is hot. Serious personal injury may result. Only remove the radiator cap from a cool engine.

  1. When removing the radiator cap, follow these procedures.
    2. 1.1. Loosen the radiator cap to the first stop. This will relieve the cooling system pressure.
    1.2. Tighten the radiator cap. This will minimize the loss of coolant when replacing the temperature sensor.
  2. Disconnect the negative battery cable. Refer to

    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.

    in General Information.
  3. Disconnect the sensor harness connector.

    4. Important: Have the new sensor ready to install or use a cork to close the sensor hole in order to minimize coolant loss.

  4. Remove the sensor.

Installation Procedure
  1. Install the sensor.
  2. Connect the sensor harness connector.
  3. Add coolant to the proper level. Refer to Draining, Filling, Recovery of Cooling System in Engine Cooling.
  4. Connect the negative battery cable.
  5. Install the radiator cap.