How Does An Oxygen Sensor "wear Out"

[bplaney]

I have read here about people replacing their O2 sensors, which I think are severally installed in the exhaust manifold, if I remember correctly.

Can someone tell me what part of an oxygen sensor wears out? is it electronic (a capacitor???) is it the degradation of some piece of rubber? what is the nature of the failure of this part?

thanks.

[2JayZ]

They "wear out" due to being exposed to the extreme heat of the exhaust system, and due to carbon build-up from the exhaust itself. There is a built in service life of about 60K miles at time of manufacture at which time most are recommended for replacement to keep the engine running efficiently and also to keep fuel economy up.

[bplaney]

They "wear out" due to being exposed to the extreme heat of the exhaust system, and due to carbon build-up from the exhaust itself. There is a built in service life of about 60K miles at time of manufacture at which time most are recommended for replacement to keep the engine running efficiently and also to keep fuel economy up.

Is there a way to tell if you have your original factory O2 sensors still in place? (for example, are they marked like I heard that spark plugs were marked)... I don't know if mine have ever been replaced. I am the third owner of a GS that has just a bit more than 101k miles on it.

If the carbon buildup can be removed (with some kind of solvent), would that extend their life, or is this even worth doing?

[SRK]

Oxygen sensor performance can be observed on modern engine scanners. If they meet normal specs, there is no need to replace them. They do not "wear out" in the usual sense. They can become contaminated from bad or leaded fuel, or become plugged externally from road dirt or water emersion. Rules of thumb, or some manufacturers recommendations, are unimportant if the sensor passes the test. It would be like asking for a heart transplant because you are 65.

[searcherrr]

I don't have a Lexus... huh huh.... huh huh....., but recently became damn near an Oxygen Sensor expert and this is the ONLY place.. and I mean the ONLY place on the web I have found the same question that I posed: "Can someone tell me what part of an oxygen sensor wears out?" - Recently I was SURE.... would've bet my life on it that 1 or more O2 sensor(s) were bad so I went out and bought all 4 of them and replaced them and the vehicle acted the same way (bad idle and bad MPG). To my disgust after all that hard DIY work I pulled the new sensors out and hopefully will get my money back for them.

Here's why I chimed in: The question of "what wears out in an O2 sensor" indeed is a good one. You would think the element that senses the air/fuel mixture would over time wear out, but it is a solid state chemical reaction that takes place and the element will always be present short of your car's exhaust reaching LAVA temperatures for extended periods of time. As long as the solid piece of element still "exists" underneath the sensor guard it will still REACT when in use and most modern day sensors begin reacting almost immediately cause they are self-heated.

This lingo "wears out at 60k or 100k miles" is simply due to the fact of which I have found repeatedly when dealing with electronics or machinery. PEOPLE DO NOT WANT TO REVIVE AN OLD PIECE OF HARDWARE. THEY/WE LIVE IN THE DAY AND AGE OF..... GET A NEW ONE... ITS FASTER AND EASIER. So then people start saying (because of laziness) that things "go bad" or "wear out" assuming no one wants to take the time to actually "FIX SOMETHING" instead of replacing it. FASTER and EASIER? Well, that all depends on how you look at things. The old saying "If it ain't broke don't fix it." pertains EXTREMELY well with O2 sensors cause short of them being physically damaged all they usually need is a good CLEANING. The only other part of the sensor that is questionable is the ceramic inside it, but as long as the sensor body is sealed I don't think I'd ever worry about it cause its just used for heat transfer.

The posts are rarely seen about cleaning the O2's because everyone "believes" the industry's verbiage so they can continue to what..... whats the magic words.... yes..... "MAKE MONEY". Pull your O2(s) out and clean'em! REVIVED for another 60k - 100k miles just like that!!! The safest method I've seen and done myself is using CRC electronic parts cleaner (picture of alternator and starter on the spray can) and you could probably use MAF cleaner as well as thats even more sensitive. I power sprayed mine clean and then soaked them in the CRC electronic parts cleaner in the little caps that come over the sensor to protect it. You could also use a small ziploc bag I imagine or a small container... small enough to fill up covering the sensor element only. I let them soak for about 2 hours. Pulled them out and power sprayed them again to get rid of loose debris and I did see debris come out when I initially pulled them out of the soak. I let them dry overnight before reinstallation. I have since reinstalled them and I have NO check engine light. I have not driven the vehicle yet though or let it run for more than say 5 minutes because I have exhaust work to finish, but others have done this method with great success.

Here is another tip: O2 sensors BREATHE!! If the TOPS of the wiring harness of the O2 sensor is full of dirt, sludge, debris etc... the sensor will NOT function correctly. Newer sensors breathe through the small gaskets surrounding the wires and use outside air for comparison to the air in the exhaust pipe. Older O2's use a breather port which I've never seen, but have read is on the side(s) of them. If ya don't wanna pull your O2's out a simple check to see if they are dirty on top where the wires go in and a spray with the recommended cleaners may help your engine run better.

Lastly, a friend of mine on another forum I'm on replaced all of his oxygen sensors cause "he thought he should due to the big recommendation in the sky as preventative maintenance" and observed ZERO MPG change. It should also be noted that OBDII vehicles 1996 and above are much less subject to needing O2 sensors replaced because of how well the computer manages air/fuel mixture over time. Pre-OBDII vehicles dirty sensors faster, but again I would bet you could just clean them and reuse'em.

[bplaney]

I don't have a Lexus... huh huh.... huh huh....., but recently became damn near an Oxygen Sensor expert and this is the ONLY place.. and I mean the ONLY place on the web I have found the same question that I posed: "Can someone tell me what part of an oxygen sensor wears out?" - Recently I was SURE.... would've bet my life on it that 1 or more O2 sensor(s) were bad so I went out and bought all 4 of them and replaced them and the vehicle acted the same way (bad idle and bad MPG). To my disgust after all that hard DIY work I pulled the new sensors out and hopefully will get my money back for them.

Here's why I chimed in: The question of "what wears out in an O2 sensor" indeed is a good one. You would think the element that senses the air/fuel mixture would over time wear out, but it is a solid state chemical reaction that takes place and the element will always be present short of your car's exhaust reaching LAVA temperatures for extended periods of time. As long as the solid piece of element still "exists" underneath the sensor guard it will still REACT when in use and most modern day sensors begin reacting almost immediately cause they are self-heated.

This lingo "wears out at 60k or 100k miles" is simply due to the fact of which I have found repeatedly when dealing with electronics or machinery. PEOPLE DO NOT WANT TO REVIVE AN OLD PIECE OF HARDWARE. THEY/WE LIVE IN THE DAY AND AGE OF..... GET A NEW ONE... ITS FASTER AND EASIER. So then people start saying (because of laziness) that things "go bad" or "wear out" assuming no one wants to take the time to actually "FIX SOMETHING" instead of replacing it. FASTER and EASIER? Well, that all depends on how you look at things. The old saying "If it ain't broke don't fix it." pertains EXTREMELY well with O2 sensors cause short of them being physically damaged all they usually need is a good CLEANING. The only other part of the sensor that is questionable is the ceramic inside it, but as long as the sensor body is sealed I don't think I'd ever worry about it cause its just used for heat transfer.

The posts are rarely seen about cleaning the O2's because everyone "believes" the industry's verbiage so they can continue to what..... whats the magic words.... yes..... "MAKE MONEY". Pull your O2(s) out and clean'em! REVIVED for another 60k - 100k miles just like that!!! The safest method I've seen and done myself is using CRC electronic parts cleaner (picture of alternator and starter on the spray can) and you could probably use MAF cleaner as well as thats even more sensitive. I power sprayed mine clean and then soaked them in the CRC electronic parts cleaner in the little caps that come over the sensor to protect it. You could also use a small ziploc bag I imagine or a small container... small enough to fill up covering the sensor element only. I let them soak for about 2 hours. Pulled them out and power sprayed them again to get rid of loose debris and I did see debris come out when I initially pulled them out of the soak. I let them dry overnight before reinstallation. I have since reinstalled them and I have NO check engine light. I have not driven the vehicle yet though or let it run for more than say 5 minutes because I have exhaust work to finish, but others have done this method with great success.

Here is another tip: O2 sensors BREATHE!! If the TOPS of the wiring harness of the O2 sensor is full of dirt, sludge, debris etc... the sensor will NOT function correctly. Newer sensors breathe through the small gaskets surrounding the wires and use outside air for comparison to the air in the exhaust pipe. Older O2's use a breather port which I've never seen, but have read is on the side(s) of them. If ya don't wanna pull your O2's out a simple check to see if they are dirty on top where the wires go in and a spray with the recommended cleaners may help your engine run better.

Lastly, a friend of mine on another forum I'm on replaced all of his oxygen sensors cause "he thought he should due to the big recommendation in the sky as preventative maintenance" and observed ZERO MPG change. It should also be noted that OBDII vehicles 1996 and above are much less subject to needing O2 sensors replaced because of how well the computer manages air/fuel mixture over time. Pre-OBDII vehicles dirty sensors faster, but again I would bet you could just clean them and reuse'em.

YES!!!

Thanks for confirming what common sense allowed me to suspect. Big picture: I am in 1000% agreement with you on the forces that would have us fork over unnecessary money to feed the beast. The turmoil we see in our economy right now is, in my opinion, the tip of a mountainous iceberg that is starting to finally come into focus for the general, non-contemplative population. That iceberg is the percentage of our economy which is total nonsense. And it is a BIG chunk of our economy. We have so completely succumbed to marketing forces, which have played on envy, fear, vanity and general laziness to sell us all sorts of crap we don't need. And now that the economy depends on sales of such crap, and we are starting to realize that we don't really need this crap, massive pain is forthcoming.

I just wish I could pocket the monetary value of, for example, the unconsumed coffee that gets poured out each morning across the country. I'd be richer than Bill Gates in short order.

[CarbonGS]

lol i shoot nitrous and that wears them out quick!

[2JayZ]

I don't have a Lexus... huh huh.... huh huh....., but recently became damn near an Oxygen Sensor expert and this is the ONLY place.. and I mean the ONLY place on the web I have found the same question that I posed: "Can someone tell me what part of an oxygen sensor wears out?" - Recently I was SURE.... would've bet my life on it that 1 or more O2 sensor(s) were bad so I went out and bought all 4 of them and replaced them and the vehicle acted the same way (bad idle and bad MPG). To my disgust after all that hard DIY work I pulled the new sensors out and hopefully will get my money back for them.

Here's why I chimed in: The question of "what wears out in an O2 sensor" indeed is a good one. You would think the element that senses the air/fuel mixture would over time wear out, but it is a solid state chemical reaction that takes place and the element will always be present short of your car's exhaust reaching LAVA temperatures for extended periods of time. As long as the solid piece of element still "exists" underneath the sensor guard it will still REACT when in use and most modern day sensors begin reacting almost immediately cause they are self-heated.

This lingo "wears out at 60k or 100k miles" is simply due to the fact of which I have found repeatedly when dealing with electronics or machinery. PEOPLE DO NOT WANT TO REVIVE AN OLD PIECE OF HARDWARE. THEY/WE LIVE IN THE DAY AND AGE OF..... GET A NEW ONE... ITS FASTER AND EASIER. So then people start saying (because of laziness) that things "go bad" or "wear out" assuming no one wants to take the time to actually "FIX SOMETHING" instead of replacing it. FASTER and EASIER? Well, that all depends on how you look at things. The old saying "If it ain't broke don't fix it." pertains EXTREMELY well with O2 sensors cause short of them being physically damaged all they usually need is a good CLEANING. The only other part of the sensor that is questionable is the ceramic inside it, but as long as the sensor body is sealed I don't think I'd ever worry about it cause its just used for heat transfer.

The posts are rarely seen about cleaning the O2's because everyone "believes" the industry's verbiage so they can continue to what..... whats the magic words.... yes..... "MAKE MONEY". Pull your O2(s) out and clean'em! REVIVED for another 60k - 100k miles just like that!!! The safest method I've seen and done myself is using CRC electronic parts cleaner (picture of alternator and starter on the spray can) and you could probably use MAF cleaner as well as thats even more sensitive. I power sprayed mine clean and then soaked them in the CRC electronic parts cleaner in the little caps that come over the sensor to protect it. You could also use a small ziploc bag I imagine or a small container... small enough to fill up covering the sensor element only. I let them soak for about 2 hours. Pulled them out and power sprayed them again to get rid of loose debris and I did see debris come out when I initially pulled them out of the soak. I let them dry overnight before reinstallation. I have since reinstalled them and I have NO check engine light. I have not driven the vehicle yet though or let it run for more than say 5 minutes because I have exhaust work to finish, but others have done this method with great success.

Here is another tip: O2 sensors BREATHE!! If the TOPS of the wiring harness of the O2 sensor is full of dirt, sludge, debris etc... the sensor will NOT function correctly. Newer sensors breathe through the small gaskets surrounding the wires and use outside air for comparison to the air in the exhaust pipe. Older O2's use a breather port which I've never seen, but have read is on the side(s) of them. If ya don't wanna pull your O2's out a simple check to see if they are dirty on top where the wires go in and a spray with the recommended cleaners may help your engine run better.

Lastly, a friend of mine on another forum I'm on replaced all of his oxygen sensors cause "he thought he should due to the big recommendation in the sky as preventative maintenance" and observed ZERO MPG change. It should also be noted that OBDII vehicles 1996 and above are much less subject to needing O2 sensors replaced because of how well the computer manages air/fuel mixture over time. Pre-OBDII vehicles dirty sensors faster, but again I would bet you could just clean them and reuse'em.

YES!!!

Thanks for confirming what common sense allowed me to suspect. Big picture: I am in 1000% agreement with you on the forces that would have us fork over unnecessary money to feed the beast. The turmoil we see in our economy right now is, in my opinion, the tip of a mountainous iceberg that is starting to finally come into focus for the general, non-contemplative population. That iceberg is the percentage of our economy which is total nonsense. And it is a BIG chunk of our economy. We have so completely succumbed to marketing forces, which have played on envy, fear, vanity and general laziness to sell us all sorts of crap we don't need. And now that the economy depends on sales of such crap, and we are starting to realize that we don't really need this crap, massive pain is forthcoming.

I just wish I could pocket the monetary value of, for example, the unconsumed coffee that gets poured out each morning across the country. I'd be richer than Bill Gates in short order.

Non contemplative? OK, dust off the soap box.

The cleaning method you guys mention must take about 2 hours - probably more. My time is worth a hell of a lot more than $30 an hour, so when you consider the $60 cost of a new oxygen sensor my afternoon is better spent just replacing the thing and calling it done properly. While you guys are scrubbing your parts I can be out donating my time to plant trees or pick up litter along the highway.

IMHO you should consider reducing the release of toxic chemicals contained in Gum Cutter and Brake-Kleen (toluene, acetone, methanol, xylene and chlorotoluene) into the environment. And, if your cleaning process fails you will continue to over-pollute the environment with your vehicle. I don't think the efficiency of a cleaned 60K mile unit can ever match the efficiency of a new unit.

Happy Earth Day everyone!

[Randy&Bonnie]

..

[2JayZ]

While you guys are cleaning your parts.... I'm sitting by the pool drinking margaritas while rock'n out to some early Jimmy Buffett :P Happy Margarita Day!!

You know what they say, if you're gonna drink all day you gotta start early! No part cleaning for me thanks... I'll spend the sixty bucks, change the part in ten minutes and then do something worthwhile with my time.

[sakataj]

im with 2jayz on this........no part cleaning for me either BUT where cn u get factory o2's for that only cost 60 bucks?

brian

[SRK]

While you guys are cleaning your parts.... I'm sitting by the pool drinking margaritas while rock'n out to some early Jimmy Buffett :P Happy Margarita Day!!

Early Jimmy!! I thought I was the only one left who liked that stuff! Very cool. I used to play "West Nashville Grand Ballroom Gown" in front of the old folks just to see if they noticed. And "Pencil Thin Mustache". I've got it all on LP of course - the original format for old people now.

[searcherrr]

bplaney:

While I feel 95% correct in my assessments/statements I have yet to run the vehicle with the newly cleaned O2's up to operating temp and for drives due to having no low speed fan to keep the engine at the right temp. I'll be 99% after I do that and then 100% after I verify the MPG I'm getting. Then the test will be complete as far as I'm concerned. I will try to remember to post back. Unfortunately I won't know for a few weeks cause I'm waiting on a manufacturer to "remake" a ypipe for me because the one they sold me does not fit 100% correct so they are actually going to remake it based off my OEM pipe not to mention waiting for a part to repair my low-fan operation.

EDIT: To clean the O2's besides removal and installation which normally would occur anyway may take you 5 minutes to set them in the solution & perhaps a brush off. You leave them there for a couple hours or even a day while you go do your community volunteer work or whatever else and reinstall after removing from the solution and let them dry. I certainly didn't sit there and watch the O2's dissolve carbon debris into the solution for several hours so I'm not entirely sure how it takes soooooooooo long to clean them.

If it doesn't work then I surely will put new ones in and retract my suggested cleaning method as a viable solution. I can admit when I'm wrong, but would I rather save $60 - $80 for 5 - 10 minutes of cleaning time? ummmmm let me think...... YES ! Wanna debate on time? How much time, gas, and $$$ spent back and forth to the parts store to get the new sensors are you gonna spend compared to cleaning the old sensors? Of course if you don't already have the electronic parts cleaner on hand you'd need to go to the parts store anyway. hehe

I think the big issue is that the vast majority of the Oxygen Sensor market is controlled by Bosch (didn't know this till recently) and because of that "EVERYONE" else who sells their sensors follows and copies their company verbiage from corporate headquarters and from their products which says when to replace them yet everywhere you look there is no explanation of why. All you get is "they wear out".

[searcherrr]

FYI - The proof in the pudding would be for someone who follows my idea to be able to capture O2 sensor data from the computer with a scan tool/logger. If the occurrence of data captured from the O2(s) is 5 or more updates per second then this is a perfectly healthy O2 sensor.

[2JayZ]

im with 2jayz on this........no part cleaning for me either BUT where cn u get factory o2's for that only cost 60 bucks?

brian

OEM style units (minus connector) can be had at thepartsbin.com. If you must have Bosch you will pay more, and you may still need to reuse the connector.

[Randy&Bonnie]

..

[lenore]

great job guys, I too am the diy. My lexus has 150k miles and original sensors. (hope I didnt jinx myself)

[SRK]

I'd like it if someone could tell me just what they think they are "cleaning" off the sensor? And switch rate is controlled by the ECM, not the sensor itself.

Stuck O2's are removed using an acetylene torch, heating to a dull red at the bung fitting, and not waiting for days for the "blaster" to soak in. No professional mechanic relies on that stuff to release seized threads.

[Randy&Bonnie]

..