longevity of O2 sensors

[Robert K]

Just wanted to post a note about how long my O2 sensors have lasted on my cars. I have a 1991 535i and changed the O2 sensor for a new Bosche unit at about 69,000 miles. The cars now has 156,000 miles and the same Bosche O2 sensor. It runs fine and gets about as good a gas mileage as it ever has, which is about 23-24 mpg highway. I also have a 1997 Camry with a V6 that has 151,000 miles, and as far as I know, its original O2 sensors. It too still drives fine and gets 29-30 mpg highway. I suppose the point of this is that changing O2 sensors at 60,000 miles may or may not really be necessary. I've read that they start degrading after a while and may not allow the engine to run perfectly. But with my present experience, I'm not so certain I really believe that anymore. I'm beginning to think that the reason we're told to change them every 60,000 miles or so is because Bosche, Denso, etc. tells us to. I get that urge every so often to replace them because I feel guilty that they're so old. But then I realize both cars are running great and figure, "Why spend the money to fix a problem you don't have?"

Just some food for thought for the rest of you out there with a penchant for changing parts regardless of whether they're worn out or not.

Grace and peace,

Robert K
1991 535i

[Morgenster]

Every mechanic I've spoken to (three) concurs on this. However: it's usually not the sensor that fails but the built-in heating element. Even this can be fixed from what I heard.

[whiskychaser]

Was looking at a UK manuf site and they recommend changing after 30K miles! I suppose they would do, wouldnt they? Mine has never had one fitted. It goes in for m.o.t. test tomorrow so we shall see how good/bad my emissions are