Rep Power: 286

i lost the manual for my 2003 civic ex. can someone tell me how often the manual says to replace the oxygen sensor?

 
Rep Power: 0

Not sure but they are cheap i had to buy a new one from honda and it was 62 bucks.

 
Rep Power: 319

I guess 62 bucks is cheap for you, that's a tank and half of gas for me though. Personally I wouldn't change an O2 sensor unless something was wrong. Maybe if I noticed the last 3 tanks of gas I've gotten really bad MPG and I run fuel cleaners on a regular basis AND I can't find any other reason why my MPG went down, then I would consider changing the O2 sensor.

But sorry, I can't help you, lol, I don't have the factory manual with me. But I do know generally an O2 sensor is rated for 100,000.

The main reason O2 sensors go bad is because of carbon build up. I take them out every 50,000 miles or so and burn the carbon off, I use little tourch thing for welding, you want the flame to be around 1500F-2000F. I work with the same ceramic material the sensors are made from, that's why I know about them

 
Rep Power: 0

when your o2 sensor goes don't you get a CEL?

that would be a good indication to me that it's time to change it

 
Rep Power: 319

If something is drastically wrong it will trigger a CEL. But the performance can decline somewhat before it will trigger the CEL, and during the time of lowwer performance, it can lowwer your MPG. But yeah, if something goes really wrong, you get a CEL.

 
Rep Power: 0

The reason I had to change it is cause i stripped it. Taking it on and off my stock to megan to random to stock again. I did not want to put a stripped o2 back in the stock cat that has the indentation. Btw it was the rear o2.

 
Rep Power: 286

yeah im only worried about the front. if my civic is anything like the old eclipse gsx i had, the front adjusts the air/fuel mix and the rear basically does nothing, just sits there and make sure the cat is working.

 
Rep Power: 453

sorda, the front o2 sensor monitors the oxygen content coming out of the engine and will send signals to the ECM and based on those signals, the ECM will adjust fuel delivery to the engine. And the rear o2 sensor monitors the oxygen content coming out of the cat and sends signals to the ECM which will determine based on those signals if the CAT is doing its job. If it isnt you get a CEL. Now I have a copy of the manaul and there is no mention of replacements for the o2 sensors, it is one of those things that usually get changed when there is a problem. If you arent getting good fuel mileage, start off checking the basics. If afterwards, check the o2 sensors for any carbon buildup. If you want, you can replace them, they are about $40 from www.hondaautomotiveparts.com