Mazda recommends the following procedures for oxygen sensor removal. This applies to 1997-2003 Protégé, 1997-2005 Miata, 1997-2002 626, 1997-2002 Millenia, 1997-2006 MPV, 2001-2006 Tribute, 2008-2010 Tribute, 2008-2010 Tribute Hybrid, 2003-2010 Mazda6, 2004-2010 Mazda3, 2004-2010 RX-8, 2006-2010 Mazda5, 2006-2010 MX-5, 2007-2010 CX-7 and 2007-2010 CX-9.
Use the following repair procedure to minimize the need to replace the catalyst converter/exhaust pipe when removing oxygen sensors and/or air-fuel ratio sensors.
To avoid personal injury, allow the exhaust system to cool before removing the oxygen sensor.
In some cases, O2 sensor seizure will occur. If seizure occurs, remove the converter or exhaust pipe from the vehicle and re-attempt sensor removal with the assembly placed in a vise. If reusing the oxygen sensor, mask it with masking tape to prevent lubrication soaking. Spray CRC Freeze-Off (or equivalent) around the flange area of the sensor. Avoid excess spraying, as remaining flammable substance could catch fire.
Allow the lubricant to reach the sensor threads for at least one to two minutes.
Turn the sensor 30 degrees counterclockwise, using SST 49 L018 001. Remove the SST and spray lubricant again in the same location. Allow the lubricant to soak for at least one to two minutes.
Use the SST to loosen the sensor. If the sensor begins to bind, it may be necessary to work the sensor clockwise and counterclockwise to slowly work the sensor out.
Wipe off all excess lubricant.
Clean the O2 sensor threads in the converter or pipe with thread-chasing tool SST J-43897-18 (available from Mazda).
If the female threads cannot be correctly cleaned on the vehicle, remove the converter or exhaust pipe from the vehicle to perform thread cleaning. If the threads cannot be correctly cleaned, replace the converter or pipe.
Coat the O2 sensor threads with Never-Seez or equivalent high temperature nickel-based anti-seize grease. NOTE: If re-using the original O2 sensor, completely remove the masking tape.
Install the O2 sensor and tighten to a value of 22-36 ft-lbs (29-49 Nm).