Engine Coolant Temperature Gauge Reads in Red Zone and/or Overheat Light On (Replace Coolant Temperature Gauge Sensor)

Some customers may comment that the temperature gauge reads in the red zone and/or the overheat light is on. The vehicle does not overheat.

This condition may be caused by an internal malfunction of the coolant temperature gauge sensor.

The faulty sensors are stamped "SPAIN" with a rectangle above the word on one of the brass hexagon flats.

Normal diagnosis, including the use of SI2000 and the Tech 2 should be performed to determine if the vehicle is in a true overheat condition. Refer to Engine Coolant Temperature Gauge Inaccurate or Inoperative and Engine Coolant Temperature Indicator Always On in the Service Manual.

Coolant Temperature Gauge Sensor Replacement

1. Partially drain the cooling system. Refer to Draining and Filling Cooling System in the Service Manual.
2. Remove the intake plenum. Refer to Intake Plenum Replacement in Engine Mechanical - 3.0L (L81) in the Service Manual.
3. Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical - 3.0L (L81) in the Service Manual.



4. Disconnect the engine coolant temperature sensor (2) electrical connector.
5. Remove and discard the engine coolant temperature sensor (2).

Important: 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 unless specified. These coatings affect fastener torque.

Important: The new GOOD sensor will have "VDO" stamped on one of the brass hexagon flats.

6. Install the new engine coolant temperature sensor (2), P/N 3439088.

Tighten
Tighten the engine coolant temperature sensor to 20 N·m (15 lb ft).

7. Connect the engine coolant temperature sensor (2) electrical connector.
8. Install the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical - 3.0L (L81) in the Service Manual.
9. Install the intake plenum. Refer to Intake Plenum Replacement in Engine Mechanical - 3.0L (L81) in the Service Manual.
10. Fill the cooling system. Refer to Draining and Filling Cooling System in the Service Manual.

GMSPO stock has been purged as of January 19, 2001 and now only has GOOD " VDO" stamped sensors in stock.

Parts are currently available at GMSPO.

For vehicles repaired under warranty, use: