alexandre
09-08-2012, 05:50 PM
Alright so as I'm getting done with all the maintenance I had planned since buying the car, I reviewed BMW's official E46 maintenance checklist to make sure everything that needed to be done was done. One of the things that stood out were O2 sensors. Nowhere in my maintenance logs (I have them for 140k until now, 209k) does it say they were changed.
BMW recommends changing them every 100k miles. Now my can of carb cleaner said that it was safe for O2 sensors. I know changing the precat sensors usually improves gas mileage and I also know that a nice cover of soot can build up with time. My question is, would it be a waste of time to just clean them and put them back in, or should I just spend the $120 for a new pair ? Are these sensors like fluid level sensors, where they either work or not, or does their sensitivity degrade over time permanently ?
EDIT: I have not had any codes related to this - it's all preventative.
BMW recommends changing them every 100k miles. Now my can of carb cleaner said that it was safe for O2 sensors. I know changing the precat sensors usually improves gas mileage and I also know that a nice cover of soot can build up with time. My question is, would it be a waste of time to just clean them and put them back in, or should I just spend the $120 for a new pair ? Are these sensors like fluid level sensors, where they either work or not, or does their sensitivity degrade over time permanently ?
EDIT: I have not had any codes related to this - it's all preventative.