M54 Rear Oxygen Sensor DIY

[richardb]

Xoutpost is disabling video embedding now I think. So here's the YouTube link:

https://www.youtube.com/watch?v=IN6_HxsKcRk&t=7s

[upallnight]

Nice video on replacing the sensor, but you should tell us why the sensor needed to be replaced. Did you get a DTC stating that the sensor needed to be replaced. What were some of the symptom of a bad sensor?

Since you were replacing the sensor, it would have been quicker to just cut the wires and use a standard deep socket to remove the sensor. This way you wouldn't be dealing with the eccentricity of the 02/crow foot socket and more torque can be applied directly to the removal of the sensor.

[oldskewel]

Thanks for the video!

I had (apparently wrongly) been under the impression that running the wires from the engine to the rear O2 sensors would involve a lot. So I had been planning to install universal sensors if the rears ever failed (mine are still original and OK at 170k+ miles). But seeing this, I will reconsider if they ever throw a code.

BTW, I replaced my upstream ones (2001 3.0i) a year ago while they were running fine. I noticed that the universal ones (Bosch 15738) apply to both upstream and downstream on these cars. So I saved the original-but-OK upstream ones I removed - if debugging the rears, maybe I can splice one of these old ones in.

Hey, also, I noticed around 1:00-1:30 in the video, views of under your car. Questions on that:
- you had the access covers in place for the access holes in the stiffening plate. How common is that? Mine are gone.
- The inspection port in the AT bell housing, letting you see the flywheel teeth, is completely open. Just like mine. I have never found a conclusive answer to whether our cars need a covering/plug there. Never been able to find a part number, etc.

[dkl]

Originally Posted by oldskewel

Hey, also, I noticed around 1:00-1:30 in the video, views of under your car. Questions on that:
- you had the access covers in place for the access holes in the stiffening plate. How common is that? Mine are gone.
- The inspection port in the AT bell housing, letting you see the flywheel teeth, is completely open. Just like mine. I have never found a conclusive answer to whether our cars need a covering/plug there. Never been able to find a part number, etc.

I had one of those access cover missing as well - not sure when it went missing (I'm the original owner). I went and did some digging and all I was able to find was the cover for the oil drain - Part# 51718268897. Turns out the cover will fit both access holes.

[richardb]

If your car has the access cover missing, it is very possible it was removed by an unscrupulous mechanic during an oil change at some point over the last... well... 15 years!

Oldskewel I would not recommend using any universal sensors for any BMW. There are two distinct part numbers, one for the upstream and one for the downstream. Honestly they are so inexpensive that you might as well just order the correct new ones.

[dkl]

Originally Posted by richardb

If your car has the access cover missing, it is very possible it was removed by an unscrupulous mechanic during an oil change at some point over the last... well... 15 years!

This is very possible - never even thought about that The car only gets oil changes at the dealers for the first 4 years of its life (free maintenance ). I've been changing my own oil since.

BTW - your DIY videos are awesome - Keep up the great work

[richardb]

For some reason the video embedding is disabled now on this site?

Here's the video link: https://www.youtube.com/watch?v=IN6_HxsKcRk&t=7s

[andrewwynn]

I just replaced my bank 1 sensor 2 last night.

My car has a vibration damper on the inboard exhaust pipe that made it impossible to get the sucker off.

I could not get enough torque on the 3/8 drive Crow foot to break it loose so I cut the cord, broke off the cap on the old sensor so I could hammer on a deep socket 1/2" drive. 25-30" of extension made it easy to break loose.



Once loose I used my Dr Seuss (goes around corners) ratchet to remove.

I used a slotted socket to do the basic install with the Dr Seuss ratchet. I used a crow foot and my torque adapter and a healthy dose of anti-sieze to install.



I couldn't fit the torque adapter on top of the straight socket but the crow foot worked perfectly. (have to make sure the crow foot is perpendicular to the breaker bar so you don't throw off the torque). 50 Nm is what I found online for the proper torque.



Picture from the outboard side of the pipes. I actually was using the thread chaser at this point = why no wires.

The Dr Seuss ratchet has a 200° infinite step swivel at the head and another 200° flex joint about 3" from the head.

It's a priceless addition to my x5 fixing toolkit. My favorite use was turning the E torx bolts that hold the rear bearings. I literally did a u turn and was installing a bolt that was pointing at me from the other side of the wheel.

[svvg]

If you’re ditching the old one, then you can smash the cermaic sensor bit with a hammer
and then a six point socket will fit over it, and you can use a big breaker bar. I’ve never been able to remove them otherwise - and the o2 sensor sockets are only good for tightening the new ones - but open up/slip shen trying to remove stuck in old sensors. I also use a thread chaser to clean out the old threads - as I ruined a £100 sensor before cleaning the threads once.

[upallnight]

Originally Posted by svvg

If you’re ditching the old one, then you can smash the cermaic sensor bit with a hammer
and then a six point socket will fit over it, and you can use a big breaker bar. I’ve never been able to remove them otherwise - and the o2 sensor sockets are only good for tightening the new ones - but open up/slip shen trying to remove stuck in old sensors. I also use a thread chaser to clean out the old threads - as I ruined a £100 sensor before cleaning the threads once.

The threads are the same as a spark plug.