2000 Buicks were equipped with a radiator-mounted coolant temperature sensor. As a secondary function, the sensor also detects when the coolant level within the radiator is low, in which case the sensor causes a light to illuminate on the instrument panel. Fortunately, replacing a defective sensor requires no specialized tools and takes only a few minutes.
Locate the sensor on the side of the radiator, just below the radiator cap.
Twist the radiator cap off of the radiator after allowing the radiator to cool. Never remove the cap when the engine is warm, as its contents are under pressure and can cause severe burns.
Position a sealable container underneath the drain bolt at the base of the radiator, then remove the drain plug with a wrench and allow the radiator to drain into the container until the coolant level falls below the level of the sensor. Replace the drain plug.
Unplug the electrical connector from the bottom of the sensor.
Lift one leg of the snap clip which secures the sensor against the radiator with needle-nose pliers, then pull the sensor out of the radiator.
Lubricate the O-ring supplied with the replacement sensor with clean radiator coolant, then position the O-ring onto the sensor.
Position the snap clip into place on the sensor, then press the sensor onto the radiator until the sensor clicks into place.
Fill the radiator with DEX-COOL coolant, then install the radiator cap.
