stupid question about the O2 sensor

[c280_ep]

OK, so I got the check engine light and it's a O2 sensor, bank 2 sensor 2, which is the one on the passenger side after the cat. But most of the online stores list the sensor as either the right side or left side. So which side is passenger side? Because you could be looking at the engine than the passenger side is the left side. But if you are seating in the car, then the passenger side is the right side. I am so confused... Anybody know?

[benzfan]

Passenger side = right side. I would think that both sides should be identical. The only difference I could think of might be wiring length. You could call up the dealer to check if the right and left sensors have the same part # just to be sure.

[jnenad16]

bank 2 should be driver's side,because the bank 1 is where the #1 cylinder is, which is the passenger side.

nenad

[benzfan]

Darn, I shouldn't try to think when I first get up in the morning. On MB, cylinder #1 is on the passenger side, so as you correctly pointed out, bank 1 is therefore on the right side. Bank 2 sensor 2 would be drivers side (left) rear sensor. Chevy has #1 cylinder on the drivers side, so it would be bank 1. On a Chevy, bank 2 sensor 2 would be passenger side (right side) rear. I had forgotten that MB #1 cylinder is on the passenger side on the "V" engines.

This should clear it up for anyone I've confused.

http://www.asashop.org/autoinc/june2002/techtips.cfm

[Polestar]

I have the same sensor failing on a '99 C280. Just to concure, it is the left after cat. sensor. ( Although under the car, it is probly right of the center line)
I found what I think is a good price on the part @ OEM Parts.com (http://catalog.eautopartscatalog.com/tayco/quote.jsp?clientid=alloemautoparts.com&cookieid=1NJ0UYFJ91NY0NITCA&baseurl=http://www.alloemautoparts.com/&partner=tayco&year=1999&product=C5010-90297&application=000596012) Also, if you go to the Bosch web site, there is a $10 gas card available with the purchase of an O2 Sensor.

[Polestar]

Will any of you who know, give me some tips on replaceing the after cat O2 Sensor?

I've been under the car and it seems rather straight forward but I don't want to screw it up.

First off, how do I physically disconnect the sending wires from their connection point. I can't quite see how they are connected up in there.
Secondly, can I expect to find the locking nut on the sensor frozen from all the heat?
If so, any tips on loosing it w/o injuring parts?
Thirdly, on install, what is the torque number and should I use an anti-seize compound on the threads?

Thanks ahead of time
:beard:

[jnenad16]

its not that hard if you have the proper tools. the locking nut should never seize do to heat since its abs plastic. the torque is given on the sensor's box(usually 20 ft/lb). if you dont have the O2 sensor socket, you might need to drop the exhaust a bit to be able to crack the sensor. also, if you cant loosen the lock nut, grab it lightly with pliers, and twist counter clock wise and it should open w/o a problem.

nenad

[martattack]

I just replaced my O2 sensors a couple days ago. It was a thorough pain in the ass. I have the inline six, so it may be different for the V6 model. I had to drop the entire exhaust system to get to them as they are on the top of the exhaust and inaccessible with the exhaust mounted.

[Polestar]

Thanks for the feedback.
The O2 sensor I need to replace is after the cat (Bank 2 Sensor2 OR G3/G5 sensor). The entire sensor is visable and uncluttered.

So the nut that holds the sensor in place is abs plastic? That must be some tuff plastic to be used on an exhust part!

I just need the free time to do the job.

[jnenad16]

the instructions I wrote are for the I6 models. if your's is a V6, then its easy, there is no lock nut on the connector, it just plugs in, and you dont need to drop the exhaust.

nenad