Upstream o2 Sensor *Picture*

[SmitsYoda]

So i replaced my o2 sensor today with a denso. Here's what the old one looked like. Can anyway tell me why it's white? My check engine light came on a while ago with the po125 code. I'm not sure if this o2 sensor is why it came on but the dealer said it was bad but im wondering what you guys can tell from the pictures?

[Downhillzze110]

if i remember right white means your burning oil and/or running lean. let me look into it but i'm fairly sure the white is soot and ash from burnt oil in the exhaust stream.
P0125 is coolant temp too low to enter closed loop OR 02 sensor heater circuit malfunction.
the white deposits could be soot and ash which could explain the code as the deposits may inhibit O2 sensor heater circuit operation. or heres a good one; have you been running unusually cool? does your car seem to take a LONG time to blow out warm air. even with highway or hard driving?

[SmitsYoda]

Originally Posted by Downhillzze110

if i remember right white means your burning oil and/or running lean. let me look into it but i'm fairly sure the white is soot and ash from burnt oil in the exhaust stream.
P0125 is coolant temp too low to enter closed loop OR 02 sensor heater circuit malfunction.
the white deposits could be soot and ash which could explain the code as the deposits may inhibit O2 sensor heater circuit operation. or heres a good one; have you been running unusually cool? does your car seem to take a LONG time to blow out warm air. even with highway or hard driving?

Actually i believe the car was running rich, i smelled gas when i drove the car. The po125 showed up, i replaced the thermostat, coolant temp sensor, new bet while i was at it. Before the car run great until it got cold this year. I'm not completely sure why i smelled gas/exhaust smells.

[Steve40th]

Generally, if you smell fuel its because the engine is running lean and the ECM adds fuel to compensate for what the O2 sensor reads.

[Shawn5800]

Its white because the sensor is made of tough porcelain.

[Steve40th]

Originally Posted by Shawn5800

Its white because the sensor is made of tough porcelain.

You might want to research that. The sensor is very similar in construction to a glow plug/spark plug. If you drop them the internals can crack as there is porcelain/ceramic materials.
But, they generally arent white like that new. That white powder looking coating in the first post is due to things being burnt onto the sensor, such as oil.They generally are a goldish/silver color, http://www.thepartsbin.com/images/ca...n_sensor_1.jpg

[Shawn5800]

I used to work in a plant that manufactured these, Its made of zirconia ceramic (similar to porcelain) . And that goldish film you see is a thin layer of platinum. The platinum burns off obviously as it ages. And your left with the aged zirconia which is white and stonish feeling. Grab it with a pair of pliers and try to snap it clean off, bet you it wont. It will crush into pieces. Just like a toilet would. Or lav.

[Steve40th]

Originally Posted by Shawn5800

I used to work in a plant that manufactured these, Its made of zirconia ceramic (similar to porcelain) . And that goldish film you see is a thin layer of platinum. The platinum burns off obviously as it ages. And your left with the aged zirconia which is white and stonish feeling. Grab it with a pair of pliers and try to snap it clean off, bet you it wont. It will crush into pieces. Just like a toilet would. Or lav.

My point being, it is a goldish silver color when new. When used, as all on mine have been, they will be either black (rich condition), or even red sometimes or a little white. Most are black or reddish.
His is that color due to ash from burnt oil.

[Andrewz]

I just got the same code, they hooked it up and told me it's the upstream o2 sensor. Did you replace it yourself? I want to do it but don't know where the sensor is located and don't have a haynes manual yet.

[Steve40th]

Here is a BOSCH O2 sensor I had in my shed. I used a center punch used asa starter prior to drilling. It puts quite the dent into metal. It didnt shatter, as I believe the part you are talking of is internal to the protective metal cover seen here. I had three different type of sensors, AC Delco, DENSO and a Bosch. I had/have 1, 2 and 3 wire versions and their covers at the end, are all different.
So, I am not disputing you on the materials made, but the three types of sensors I had all have a metal protective sheaths, to protect the internal parts, which are more than likely a ceramic material. I have never seen an O2 sensor where the ceramics are exposed to the elements allowing them to break very easy during install. You can see the exhaust gas goes into the O2 sensor where the ceramic portion does its thing.
And the long portion of the senor above the nut where you tighten is where the critical parts of the ceramics are.
So, back to the original posters question as to why his is white, it is because of burnt oil.

Here is an excellent picture of there construction
http://www.sixity.com/images/012000000diagram.gif

[Andrewz]

Does anyone have a picture or an idea of where the upstream sensor is located? I was hoping to get this done today, got the new sensor. Thanks.

[Steve40th]

Look by at the back of the engine, follow the exhaust down and you will see it. The wire harness goes towards the drivers side of the valve cover. Soak the bolts with a good penetrant for awhile.

[Andrewz]

Originally Posted by Steve40th

Look by at the back of the engine, follow the exhaust down and you will see it. The wire harness goes towards the drivers side of the valve cover. Soak the bolts with a good penetrant for awhile.

Thank you!