White Deposits on Oxygen Sensor

[The Critic]

The SES light was illuminated on the Saturn @ 114k, so I retrieved the code, which was a P0133. This indicated a slow response from the upstream oxygen sensor, so I replaced it with a Bosch "OE style" unit for $64.99 from AutoZone.

While the car runs significantly better now (more peppy, much smoother, no more gas odor during idle), I'm rather concerned about the white deposits that were present on the old sensor. I'm afraid that I have another condition going on, and it may kill the new sensor as well. Here's a picture of the old sensor, and I would appreciate it if someone could tell me what these white deposits are from.

Thanks!

 

[ewetho]

When you get too much gap or run lean plugs go white so I imagine it was running lean.

 

[Pablo]

Could be a coolant leak. When was the last UOA?

 

[Mr Nice]

Were you using any gas additives ?

 

[The Critic]

Originally Posted By: Pablo
Could be a coolant leak. When was the last UOA?

I've never done one before on this car. I did have some coolant loss at one point, but it has yet to happen again.

I heard that the whitish coating could also be from fuel additives, silicone based sealers or bad fuel. Any truth to that?

 

[stroked93]

I did a head gasket once, the exhaust looked white like that from coolant.

 

[Pablo]

A sign of some type of silicone or other contaminant/additive that leaves a white coating.....It's possibly from the fuel, but I would think that your plugs would looks similar as well. Check a plug.

 

[Gary Allan]

I don't KNOW ..but I wouldn't get upset about finding this. I'm more annoyed when I find the sensor sooted (like it appears closer to the threads).

 

[Quest]

gasoline additive or coolant related.

ewetho- the O2 sensor shield is made of something similar to stainless steel so unlike white ceramic electrode tip of a spark plug that runs hot/lean, the white you see is from deposits and not from the ceramic body of a spark plug tip.

I would keep a look out on gasoline quality and/or head gasket failures. If it's not related to latter, then it's very likely to be gasoline brand related. I've seen quite a few of these coloured O2 sensors during my days where certain gas stations here uses MMT as additive (or something undisclosed).

Q.

 

[mechtech2]

Looks normal to me. The deposits are not heavy, in any case.
They are installed in a HOT exhaust location.
Could be a bit of oil burning going on.

 

[The Critic]

Originally Posted By: LT4 Vette
Were you using any gas additives ?

I think I used STP Complete Fuel System Cleaner once and Chevron ProCarb twice. That was about 30k ago.

 

[Cup of Joe]

Fella's seriously. I have never pulled a O2 that didn't look exactly like that. Including sensors that had been working just fine and where re-used. There is nothing wrong, just a bad sensor.

Everyone go out and pull your sensors I'll wait.