Arma 134 Report post Posted November 27, 2014 (edited) So several maintenance checklists state the o2 sensors need changing every 100k kms apparently. Now my question is - is this something worth doing a preventative maintenance on, or should I wait till I start seeing some symptoms of it failing? Am asking because I'm not sure whether waiting for symptoms would cause knock on effects and cause issues elsewhere in the car (e.g. cat converter). My 530 is at ~114k kms now, and I don't have any old service history stating whether it's ever been replaced. Or are these maintenance lists just very pedantic and these don't go bad that quickly? (I understand it can vary from car to car obviously)Edit: Just re-checked, the lists state 100k miles, not kms . Anyway, still asking the question, just 60k kms early. Edited November 27, 2014 by Arma Quote Share this post Link to post Share on other sites
Auzeras 28 Report post Posted November 28, 2014 Generally you wait till the OBD throws a code, no way to tell it's bad until it's bad as far as I know. The O2 sensor only provides correctional data to trim the mixture to perfection. It will (or should) run fine without one on older cars. Newer ones have so many efficiency improvements a bad O2 can throw things quite out of whack. Not enough to wreck anything, but you'll see a reduction in power. Cats get wrecked by unburned fuel, even without the O2 sensor you shouldn't be running that rich, you can replace as preventative but IMO I'd wait. 1 Quote Share this post Link to post Share on other sites
