What size wrench do I need for my O2 sensor?
What size wrench do I need for my O2 sensor? 7/8" (22mm). Many times the O2 sensor will be bound pretty tightly, an open end wrench will most likely round off the hex. Get an O2 sensor socket, or you can get a regular deep 7/8" socket, cut the wires to the old O2 sensor, and take it off with the regular socket. How big is an O2 sensor socket? 22mm (22mm) socket fits most oxygen sensors". Do you need a special tool to remove O2 sensor? Do You Need A Special Tool To Remove O2 Sensor? 1 Wrench set...