O2 sensors

Redd · 09-20-2019, 11:43 AM

Is there a recommended mileage to replace O2 sensors, or just use until they break? Car is a 2010 with 127k kms and still on original O2 sensors. No issues, running fine. Just wondering if preemptively replacing them is a good idea.

randrews15 · 09-20-2019, 02:27 PM

Most of the time BMW recommends replacing O2 sensors at 100k miles. My son's Audi is the same and it has 137k on the clock with original sensors. It runs fine but probably would improve with new sensors. Take it for what it's worth and maybe plan to change them as PM.

dparm · 09-20-2019, 04:00 PM

My two cents: if you're gonna be under the car and have access to them, may as well do it. A bad O2 sensor won't leave you stranded on the side of the road but the dashboard will light up like a Christmas tree and it'll run like shit until you limp it home.

Lots of stuff like misfires, "car feels slow", and other drivability complaints are symptoms of flaky O2 sensors.

Also, when replacing them, be sure to inspect the connectors and wiring for damage. Clean the connectors with electronics cleaner as well.

Jims M3 · 09-20-2019, 05:18 PM

I replaced all 4 just recently it really is a very easy job. I had 94k miles on my car. I was starting to get Misfire soft codes, and going lean is not a good thing. I got mine from FCP for $400 for all 4, and then now have a lifetime warranty on them.

Ajolives · 09-20-2019, 06:03 PM

Buy a scan tool. I got one at Harbor Freight for $270 that scans codes and reads live data. Also scans monitors and I used it to register my battery.

It's a much better investment in the long run to actually try and diagnose your car versus just throwing parts at it because everyone tells you to. You can use the live data function to look at the O2 sensor cycle and tell if it's still working within standards.

Redd · 09-20-2019, 06:44 PM

Thanks all. Next question - should I replace all 4, or just the front ones? My car is completely de-catted.

dparm · 09-20-2019, 08:33 PM

Quote:

Originally Posted by Redd

Thanks all. Next question - should I replace all 4, or just the front ones? My car is completely de-catted.

Replace all four if you can afford it.

mapster37 · 09-20-2019, 10:57 PM

no need to replace all four if you are de-catted. the secondary 02's main purpose are to monitor the catalytic converters.

Redd · 09-21-2019, 03:54 AM

Quote:

Originally Posted by mapster37

no need to replace all four if you are de-catted. the secondary 02's main purpose are to monitor the catalytic converters.

Thanks!

09-20-2019, 11:43 AM	#1
Redd Brigadier General 3900 Rep 4,164 Posts Drives: 2010 BMW E92 M3 Dakar Edition Join Date: Jul 2015 Location: Malaysia iTrader: (0)	O2 sensors - When to replace? Is there a recommended mileage to replace O2 sensors, or just use until they break? Car is a 2010 with 127k kms and still on original O2 sensors. No issues, running fine. Just wondering if preemptively replacing them is a good idea.
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09-20-2019, 02:27 PM	#2
randrews15 Lieutenant 289 Rep 553 Posts Drives: 2012 E93 M3 Le Mans Blue Join Date: Nov 2012 Location: Parrish, FL iTrader: (1)	Most of the time BMW recommends replacing O2 sensors at 100k miles. My son's Audi is the same and it has 137k on the clock with original sensors. It runs fine but probably would improve with new sensors. Take it for what it's worth and maybe plan to change them as PM.
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09-20-2019, 04:00 PM	#3
dparm Stop the hate, get a V8 3850 Rep 8,625 Posts Drives: C7 Corvette GS, AMG C63 S Join Date: Jun 2013 Location: Frisco, TX iTrader: (1)	My two cents: if you're gonna be under the car and have access to them, may as well do it. A bad O2 sensor won't leave you stranded on the side of the road but the dashboard will light up like a Christmas tree and it'll run like shit until you limp it home. Lots of stuff like misfires, "car feels slow", and other drivability complaints are symptoms of flaky O2 sensors. Also, when replacing them, be sure to inspect the connectors and wiring for damage. Clean the connectors with electronics cleaner as well. __________________ Now: 2017 Corvette Grand Sport, 2021 AMG C63 S sedan Past: 2011.5 M3 sedan ZCP
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09-20-2019, 05:18 PM	#4
Jims M3 First Lieutenant 454 Rep 312 Posts Drives: F95 X5M, F80 M3, C7 Z51 Join Date: Jan 2013 Location: Aledo, TX iTrader: (1)	I replaced all 4 just recently it really is a very easy job. I had 94k miles on my car. I was starting to get Misfire soft codes, and going lean is not a good thing. I got mine from FCP for $400 for all 4, and then now have a lifetime warranty on them.
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09-20-2019, 06:03 PM	#5
Ajolives Captain 922 Rep 933 Posts Drives: E90 M3 Join Date: Mar 2019 Location: Tampa iTrader: (0) Garage List 2019 Audi SQ5 [0.00] 2008 BMW M3 [0.00]	Buy a scan tool. I got one at Harbor Freight for $270 that scans codes and reads live data. Also scans monitors and I used it to register my battery. It's a much better investment in the long run to actually try and diagnose your car versus just throwing parts at it because everyone tells you to. You can use the live data function to look at the O2 sensor cycle and tell if it's still working within standards.
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09-20-2019, 06:44 PM	#6
Redd Brigadier General 3900 Rep 4,164 Posts Drives: 2010 BMW E92 M3 Dakar Edition Join Date: Jul 2015 Location: Malaysia iTrader: (0)	Thanks all. Next question - should I replace all 4, or just the front ones? My car is completely de-catted.
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09-20-2019, 10:57 PM	#8
mapster37 Captain 362 Rep 924 Posts Drives: F80 Join Date: Sep 2018 Location: Davie iTrader: (2)	no need to replace all four if you are de-catted. the secondary 02's main purpose are to monitor the catalytic converters.
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