O2 Sensor

[RRoller123]

Does the O2 sensor need to make excellent grounding to the exhaust pipe? It produces such a small voltage output, like an average of 4VDC or thereabouts. I am wondering if a little aluminum anti-seize on the threads would be a problem. Ordered a new one and getting the old one out is tough. I have a 24mm deep socket wrench, but use of that requires cutting the wire lead, which works fine taking it OUT, but not so much putting the new one IN....

Will try and use an offset wrench I think. Just a little tight in that area for use of that wrench. First time changing one, any tips?

[TX82FIAT]

You can buy a specific socket for the O2 sensor for something like $8 at harbor freight for the 3 or 4 lifetime uses. I would use the copper unseize sparingly on the thread only. Don't let any seize contact the sensor.

[RRoller123]

Thanks! I have a HF very close buy, I will check that out, and use the Cu versus Al anti-seize.

Pete

[SteinOnkel]

The 02 sensors are a little sensitive. Don't let anything touch the tip of the sensor. No grease, oil, brake cleaner etc.

They are grounded with the wiring harness, not with the exhaust. Grounding electrical components on the exhaust is a big no-no.

Good Luck
Steiny

[RRoller123]

So there seems to be a woven shield around the sensor wire, that gets grounded back through the harness, and the unit itself is electrically isolated from the exhaust?

[DieselSpider]

Be very careful about any chemicals, sealants, etc that you use on an engine with an Oxygen Sensor. Even the fumes from using an incorrect RTV sealant on an engine crankcase or intake joint can cause an oxygen sensor to fail completely or give inaccurate readings back the the ECU.

[RRoller123]

Thanks, has no idea that it was that sensitive!

[RRoller123]

A tip on removal and installation of the O2 sensor:

A 24mm Deep Socket will do it, but the wire has to be cut to use the socket..... ok for removal, not so good for installation.

A 7/8" Offset 12-Point Box Wrench does the trick. Fits perfectly, and you don't have to remove the AFM.

The O2 sensor came right out with little effort, no PB Blaster. A bit surprising. Nothing appears to have been put on the threads, but the sensor is quite clearly perished.

[axelbaker]

So there seems to be a woven shield around the sensor wire, that gets grounded back through the harness, and the unit itself is electrically isolated from the exhaust?

That shielding is to protect the signal from noise from your ignition system.