Never owned or built a car (post 80s') with any emissions sensors or restrictions.
I just changed my pre-cat (upstream) 02 sensor in my 104kmi '04 R53 today.

Does this 02 sensor say anything about the operating/running condition of the car?

Left - 104kmi pre-cat / Right - new NTK replacement

I can fairly read the condition of a spark plug (e.g.: too lean, too rich, spark advance, blown oil ring..) but have no experience with 02 sensors.

Just curious if the white-sh color is an indication of a lean condition?
I never had any fault codes or SES light pointing to a bad 02. But to the best of my knowledge/records; neither 02's have ever been changed.
Just thought it might be a good time to change out the sensors while performing some general maintenance.

Thanks!

 

After googling around a bit with regards to the white-sh appearance/residue; some information point to "silicone poisoning" which is due the the use of silicone (gasket) sealant.
Other information suggests is a result of a "lean condition".
With regards to the first assessment; It struck me as a bit odd - I can honestly state that I've done a ton of work to this car and have never used any silicone gasket sealer with any of my replaced gaskets, parts or repairs.
That's not to say that in the past (12 years ago, before I began performing repairs myself), that other repair shops had perhaps used sealant in their repair work.

Perhaps silicone is present in the oil I've been using? - 'been using Mobil1 5w20 or 30 for 19 years.

It's not a big deal. Just curious as to what the white color is.

Still interested in your thoughts

 

It doesn't say anything about your engine. If you want to determine if your engine is running properly, and the O2 sensor is switching like it's supposed to, you'll need a diagnostic scan tool and observe the upstream O2 sensor; It should switch from .2 volts to .8 volts at a frequency of 1-5 times per second. To see the frequency, you'll need a lab scope since scan tools don't measure on the x axis in time, but in frames. You can also pull up short-term (STFT) and long-term (LTFT). Perfect fuel trim will be around zero with an acceptable range of -10 to +10.

 

The color doesn't strike me as unusual or cause for concern.
Take a look at the plugs and as mentioned above check your fuel trims with a scanner if you're still unsettled.

 

Hey thanks for the feedback!
I should have phrased my question more concisely.
"Has anyone seen this white condition with their upstream 02 sensor?" Or "Is this normal?".
(I wasn't experienced with 02's to make an educated assessment)

Yes I do have some data previously recorded from my OBDII (before the 02 change):
02 sensor 1 (pre-cat) = 0.700V
STFT sensor 1 = 0.0
LTFT Bank 1 = 10.0 - +11.7

02 sensor2 (post cat) - 0.210V
STFT sensor 1 = -0.08
LTFT = ?
Intake Absolute pressure = 5.8 - 6.1
Intake air temp = 138º

The car runs and performs just fine w/no concerns.
According to my records; the 02 sensors have never been changed in the last 20 years.
I've got near 30k mi on my plugs, wires and refurbished JCW 380 injectors but intend to change the plugs as part of my 30k maintenance service.