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View Full Version : when should oxygen sensors be replaced?



bobcat
10-16-2003, 06:31 PM
when should oxygen sensors be replaced? 50k, 75k, 100k miles, or never?(until it fails)

Thanks! :bunny:

manny
10-16-2003, 07:21 PM
75 k miles is reasonable.
They are considered a " maintenance " item. ;)

SLAMMED_C
10-16-2003, 08:49 PM
Honestly I wouldnt replace them unless they need to be replaced.. i.e. check engine light on and the o2 sensor is the reason.. only if faulty I say.

WeatherMan
10-17-2003, 04:34 AM
.

CKlasse
10-17-2003, 06:04 AM
Originally posted by WeatherMan
I've replaced 3 in the last 9 months waiting for them to fail and getting the CE light, in a range of 30-40k miles.

3 in 9 mo. on the same car would suggest something else is wrong, not the sensor. :)

Luwin1026
10-17-2003, 07:16 AM
I don't know crap about oxygen sensors, but it's so good to see you back posting, BOB!!!! :D

manny
10-17-2003, 07:27 AM
Originally posted by WeatherMan
I've replaced 3 in the last 9 months waiting for them to fail and getting the CE light, in a range of 30-40k miles.

Could you be more specific on the reasons & symptoms ?

manny
10-17-2003, 07:33 AM
Originally posted by SLAMMED_C
Honestly I wouldnt replace them unless they need to be replaced.. i.e. check engine light on and the o2 sensor is the reason.. only if faulty I say.

Yes, you could also wait til your fuel mileage gets really crappy, you partially plug up a catalytic converter, or fail an emissions test. ;)

WeatherMan
10-17-2003, 07:35 AM
.

manny
10-17-2003, 07:52 AM
Have never seen 3 O2 sensors go bad in such short order.
Something else is being missed here.
The pinging & popping ( in the exhaust I assume ) is interesting.
Sounds like running too rich & overheating.
You may want to try another repair facility.
A dyno run may help pinpoint the cause as well, as you could at least locate the noise.
My money is on something to do with the exhaust ( plugged ? ).

CKlasse
10-17-2003, 08:03 AM
.. or you can stop guessing and simply put your car on the DSO. It reads everything from your ignition, MAS, and O2 sensor and the emission gas at THE SAME time.. Pretty cool tool. You'll detect the prob. very quickly.

Ask a diagnostic guy to look at your car also, dont just rely on the techs. A bad 2nd bank O2 reading might means bad O2 sensor or bad cats. Bad 1st bank O2 reading can means anywhere from your MAS, ignition, fuel etc to the O2 itself.

Good luck to you.

Renn 208
10-17-2003, 09:22 AM
Originally posted by Luwin1026
I don't know crap about oxygen sensors, but it's so good to see you back posting, BOB!!!! :D

big :werd: Welcome back dude!

Tump43
10-17-2003, 02:21 PM
CKlasse and Manny are right on the money. O2 sensors are definately maintenance items. Bosch itself recomends that they be replaced every 60K miles (Bosch makes the Benz O2 sensors). In my case, I replace them every 50K miles.

When I replaced them on my C43, gas mileage improved, the engine ran more smoothly and quitely, and acceleration seemed to improve. That last item, however, may be due only to my imagination and replacing the OE Benz air filters with RamFX high flow foam filters.

I believe in the "better safe than sorry" philosophy when it comes to O2 sensors and other maintence items, such as fluid changes (syn oil, tranny fluid, diff. oil, brake fluid, power steering fluid, MB coolant and, of course, alleged Bosch "100K" spark plugs -- change them at 50K miles as well).

manny
10-17-2003, 03:09 PM
Tump43

Thank you. I feel somewhat vindicated. :)

manny
10-18-2003, 11:49 AM
For anybody who wants to know.
Pick up the November copy of Road & track magazine.
On page 170, your questions about O2 sensors will be answered. :)