Oxygen Sensors, Replacing as Preventive Maintenance

[Terkins]

http://www.obdii.com/articles/Replacing_Oxygen_Sensors_Preventive_Maintenance.pdf

"A good oxygen sensor is essential for good fuel economy, emissions and performance. If a vehicle with a sluggish O2 sensor is only averaging 18 mpg, and is driven 12,000 miles a year, replacing the sensor can save $100 or more a year in fuel bills if the new sensor improves fuel economy 10 percent to 15 percent (which it often can). It’s not a big savings, but there are other benefits, too. As we said earlier, bad O2 sensors are a major cause of emission failures, as well as a leading cause of catalytic converter failures. Replacing an aging O2 sensor for preventive maintenance, therefore, is recommended not only to restore peak fuel efficiency and to minimize exhaust emissions, but to also prolong and protect the life of the converter, too."

 

[J_C]

Meh, I don't buy into that. People who drive that much with a vehicle getting such low MPG aren't all that interested in the fuel costs.

it'd cost me over $110 to replace all 4 and I don't drive my older Explorer anywhere near 12K mi/year. Frankly I wouldn't advise people who are putting on that many miles a year to pour money into 10-15% improvements for a vehicle that only gets 18MPG. At that rate you're spending nearly as much on fuel per year as the vehicle is worth, could just switch to something getting 30+MPG instead and save around $600+ per year on fuel, or more if fuel prices go back up. Plus at that yearly mileage rate you're going to be racking up more (other) repairs soon too, probably including a few tow bills.

Then again if I were putting on 12K mi a year then it'd be hitting 100K mi. before it was 9 years old and a lot of those miles would have to be (easy) highway miles, in that case I can see the vehicle otherwise expected to have more of its lifespan remaining.

On the other hand if it's running poorly or won't pass an emissions test, sure. Besides my leading cause of catalytic converter failures is rust due to winter salted roads.

Overall the article reads to me like an author trying to pretend things are more significant than they are, based on statements by companies that make O2 sensors. For example you "can save $xyz IF it improves economy by 10-15% (which it often can). In other words a lot of times it won't.

At least the article did mention some good info about looking at the sensor values to determine if the sensor feedback is sluggish, but if there are that much deposits accumulating on the sensor, they're getting on the cat too so you can't say a little bit off sensor caused cat failure rather than that the same soot that fouled the sensor also fouled the cat.