The Oxygen (O2) zirconia cell is very sensitive to contaminants.

The following illustrations show poisoned O2 Sensors. Contamination will make the sensor function inaccurately, which will lead to poor performance, poor fuel economy and high emissions.

Leaded fuel will turn the sensor tip a light pink color.

An internal coolant leak will turn the tip of the sensor a green whitish brown color.

Using RTV silicone that is not sensor safe will turn the O2 tip a whitish color.

An engine burning oil will turn the tip of the sensor a brownish color.

Check your O2 sensor with Tomco's Oxygen Sensor Tester.

Copyright 2005 Tomco, Inc. All rights reserved.
Last Updated: January 22, 2005 4:00pm CST