$700 to replace 02 sensor?

[hip check]

My car is scheduled this Saturday for its regular service. The dealership said that at 100k you should also replace the 02 sensor and quoted a price of $700--Ouch!

My questions are:
1. Is this an easy DIY project?
2. Can I get the sensor cheaper somewhere other than the dealership?
3. Is it necessary to replace the sensor if the current one is working fine?

Thanks for any help with these questions,

Mitch

[DneprDave]

I haven't changed an O2 sensor on a MINI, but I've done them on other cars, it isn't difficult to do. There is a special socket that makes it easier to do, you can get it at Harbor Freight. Outmotoring sells MINI O2 sensors for $250, but they are probably made by Bosch and you could get a get one of those for a lot less.

I wouldn't change it until it fails, you will know when it fails, it'll throw a code and the check engine light will come on. You can still drive it with a bad O2 sensor, so you won't get stranded.

My Volvo has the original O2 sensor and it has 184,000 miles on it.

Dave

[Agent99]

I looked into this a little a year ago and there are some DIY instructions online. It didn't look too difficult. Mini Mania has the part for $285.00.

"Factory replacement O2 Sensors, pre and post cat (sold individually). A defective O2 sensor can trigger the Service Engine light and also affect your MINIs gas mileage. Sold individually, get this sensor to replace either the pre-cat or post-cat sensor, or both.
For 2002-2006 R50 MINI Cooper and R53 Cooper S Hatchback, and for 2005-2008 R52 MINI Cooper and Cooper S Convertibles.

About O2 sensors:

An O2 sensor (lambda sensor) has an expected life span of about 30,000 to 50,000 miles. Sensors may fail prematurely if clogged with carbon, or contaminated by lead from leaded gas or silicone from an antifreeze leak or from silicone sealer.

O2 sensors become sluggish as they age. Eventually the signal does not change at all. When this happens, the EML and/or check engine light may come on, and the engine may experience drivability problems or damage caused by an overly rich fuel condition. High fuel consumption, high CO and HC emissions, poor idle, and/or hesitation during acceleration are typical complaints.

If the average voltage from the O2 sensor is running high (more than 0.50V), it indicates a rich condition, possibly due to a bad MAP, sensor or leaky injector. If the average voltage reading is running low (less than 0.45V), the mixture is running lean possibly due to a vacuum leak or because the sensor itself is bad. If the O2sensor continually reads high (rich), it will cause the engine computer to lean out the fuel mixture in an attempt to compensate for the rich reading. This can cause lean misfire, hesitation, stumbling, poor idle, high hydrocarbon emissions (from misfiring) and engine damage.

If the O2 sensor continually reads low (lean), it will cause the engine computer to enrichen the fuel mixture. Injector pulse width will be increased causing fuel consumption and carbon monoxide emissions to go up. Especially in a performance tuned vehicle, a constantly rich fuel mixture can cause the catalytic converter to overheat and it may be melted." - from the MINI Mania website.

[Pinky]

Unless your getting an SES light or noticing some drivablity problems it really isnt worth the cost of replacing the sensors.

Pinky recently had the SES light come on, the code reader told me it was the pre-cat o2. I've been researching the DIY method. Reading about other peoples experiences Bosch o2 sensors seem to continue to throw a code. The NGK/NTK seems to be very popular as well. So far I haven't read about SES light issues with the NGK.

Right now Amazon has the "forum recommended" Bosch 13878 Oxygen Sensor, OE Type Fitment by Bosch for $99, & NGK 25648 Oxygen Sensor - NGK/NTK Packaging for $115.

However, this is the begining stages of my research, so only take it with a grain of salt. :D

[phydeaux]

I can't imagine that an O2 sensor is that hard to replace. You and I can do it in the driveway one day, Mitch. I've got ramps, a decent tool set (no special socket from Harbor Freight, but there is one of those just down from Valley Medical), and both the wheeled and cardboard creeper. What more would we need? Oh, yeah, a clue would be good. ;)

[Pinky]

So Mitch, did you decide to get it done?

[hip check]

I decided to hold off and just had them do the remaining service items. Thanks to ROTQ, my service was free this time.

Mitch

[Agent99]

That is cool! Glad you could use the ROTQ for the service. :)

[MINI-Rolls]

Mitch,

Cleaning up my office I came across a letter from MINIUSA stating they are extending the warranty on 04-06 MINI's for the O2 sensor to 10 years or 100k milles. If they say it needs to be changed have them do it under this extended warranty.

[hip check]

Dang Dave. My car is at $107k now so I'm not within that warranty

[MINI-Rolls]

Sorry, was sure of your mileage......