How to Replace the Oxygen Sensor on a Chevy

The oxygen sensor or sensors on your Chevy vehicle are not difficult to replace once you unscrew the units. Yet, since they ride on the exhaust pipes, the sensors' threads tend to seize to the pipes, making it difficult and dangerous to remove if you are not careful. We recommend the use of penetrating oil a few hours ahead of the job, if necessary. This will not only make your job easier but will help you avoid damaging the mounting threads on the pipes and costly repairs. Once you have the exact replacement for your particular Chevy model, follow these steps to install them.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Penetrating oil, if necessary
• Floor jack
• Two jack stands
• Box-end wrench or ratchet and sensor socket
• Anti-seize compound

Remove the Oxygen Sensor

1. Warm up the engine for about four minutes to bring it to operating temperature. Then turn off the engine. This will avoid damage to the exhaust pipe threads if that sensor has seized to the pipe.

2. Find the oxygen sensor or sensors you need to replace. The upstream sensor is located near the exhaust manifold and the downstream sensor on the back exhaust pipe, close to the catalytic converter.

3. Disconnect the oxygen sensor electrical connector. Depending on your particular Chevy model, both sensors may be disconnected from the engine compartment.

4. Lift the front of your Chevy model to reach the sensor you need to change, if necessary. Use a floor jack and two jack stands to support it.

5. Remove the oxygen sensor using a box-end wrench or a ratchet and oxygen-sensor socket.

Install the Oxygen Sensor

6. Apply a light coat of anti-seize compound to the threads of the new sensor. Avoid touching the tip of the sensor with the compound, which may ruin the unit.

7. Start the new sensor by hand on the exhaust pipe. Then tighten the unit using the box-end wrench or ratchet and oxygen-sensor socket.

8. Connect the sensor electrical connector.

9. Lower the vehicle if you had to lift it.

Tips & Warnings

• If you need to verify the number and location of the oxygen sensors on your particular Chevrolet model, consult your vehicle service manual. Most auto parts stores have these manuals in stock, and your local public library may have one on hand in the reference section as well.
• It only takes a few minutes for the exhaust system and related components to reach very high temperatures. To avoid serious skin burns, wear long-sleeve shirts and working gloves if necessary. If you have to work underneath your Chevy, wear goggles to protect your eyes from dirt, rust and other particles.

References

• General Motors Chevrolet Cavalier & Pontiac Sunfire 1995 thru 2004; J. H. Haynes and D. M. Stead; 2005

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