Replace an Oxygen Sensor

Most oxygen sensors screw into the exhaust pipe. When it’s time to replace an oxygen sensor, you’ll need an oxygen sensor socket. Some oxygen sensors screw into the exhaust pipe. But air/fuel ratio sensors usually bolt onto the exhaust manifold. Many DIYers refer to them as oxygen sensors. Here are the instructions for removing screw-in style oxygen sensors.

Buy or rent an oxygen sensor socket set

Screw in oxygen sensor

Oxygen sensor sockets are special tools that allow you to easily replace an oxygen sensor, even if you’re working in limited space. Just slide the socket over the sensor, The cut-out on the socket allowsspace for the wiring harness.

You’ll also need a long handled ratchet and a can or rust penetrant.

Step 1 to remove an oxygen sensor

Soak the sensor with rust penetrant when the exhaust is cold.

Wait about 15-minutes for the penetrant to seep into the threads. Then, using a ball peen hammer, tap the oxygen sensor multiple times to set up vibrations that will break up the rust and allow the penetrant to seep in even further. Apply more rust penetrant and hammer again. Vibration is key to breaking up the rust.

Step 2: Start the engine and warm up the exhaust

Heat will help. But you don’t want the exhaust so hot that you can’t work safely. So start with warm. If you need more heat, you can try heating the sensor with a propane torch. Just be careful that the heat doesn’t damage the oxygen sensor wiring harness.

Step 3: Insert the oxygen sensor socket and apply force

A lot of force. If you can’t get enough leverage using a 3/8″ inch drive ratchet, add a 3/8 to 1/2″ adapter and use a 1/2″ drive breaker bar.

Once the old sensor is out, install the new sensor

Most new sensors come with anti-seize pre-applied to the threads. Or, they’ll have a tube of anti-seize in the box.

If it’s not pre-applied, coat the threads of the sensor with anti-seize before installing.

Refer to the instructions or a shop manual for the proper tightening torque.

© 2012 Rick Muscoplat

Posted on November 4, 2023 by Rick Muscoplat