I have read that O2 sensors should be replaced every tune-up, or every 30,000 miles, or every 100,000 miles. Is there any guidelines for the average life of the O2 sensors or do you just wait for them to fail?
I think it depends on the car, but for my E30 it used to be 60k miles. O2 sensors aren't cheap, so personally I'd just wait for it to fail again, but modern O2 sensors I think can last 100k miles.
I have 107K miles and just changed them. I noticed that fuel economy wa sslipping so I did some digging. Apparaently, the sensors do degrade over time and should be changed for best performance not later than 100k miles due to excessive wear but you might not get a "failure" indication (Check engine light). I went to Pelican parts and changed all 4 sensors (2 prior to cat and 2 after cat) for about $380. Did it myself and saved a ton of $$. Easy repair with noticeable improved fuel economy.
Same here. Every 30,000 is too often. I replaced mine at 120K after procrastinating for several months. It's a fairly easy DIY job. Do yourself or the next guy a favor: Put a little anti-seize compound on the threads (but not the sensor tip!) when installing the new ones.
