Post Cat O2 Sensors? **SOLVED**

[MPDano]

Hello All,

I can't seem to be able to find a write up on replacing them.

Thanks,
Leo

[upallnight]

Crawl underneath the truck with an O2 socket, disconnect the O2 connector, place O2 socket on the O2 sensor and remember righty tighty, lefty loosey, remove the O2 sensor

Here's a Youtube video for an E39, which is similar to our E53.

https://www.youtube.com/watch?v=MXb8mkhwNgc

[romeokc10]

You don't need an O2 socket, you can use a regular wrench, they're easy to get to, I took my right rear one out yesterday, took 15 minutes.

[upallnight]

I normally cut the wire and use a deep socket with a breaker bar to remove O2 sensors.

[MPDano]

Do I need to remove the large pan? Also, once in there, will I see the connector?

Thanks

[TiAgX5]

Why are you replacing them?

[MPDano]

Got an error code. Not at home to give the code but found the code to be the "post" O2 Sensors.

[romeokc10]

If you're on the road just wait until you get home, it won't affect anything.

[MPDano]

Okay, since there is no write-up on doing this. Here it goes as I did mine plus replaced the power steering pump and door handle assembly.


BMW X5 2004 3.0 POST O2 Sensor Removal/Installation

1) Remove the center plastic piece on the engine, two 10mm bolts
2) Jack up the passenger side of the car as this is where the O2's are routed.
3) One at at a time, use a 7/8 Wrench on the closest one to engine. Remove the O2, then go to the center top of engine and unplug one and see if you can pull it up. If so, pull up and then replace with a new one. If not, re-plug and unplug the other and pull up.
4) Feed the new O2 just center and to the passenger side of the firewall. It will literally drop just where it needs to be.
5) I usually give the sensor a few twists counter clock since your going to screw the new sensor clockwise.
6) O2 sensor furthest from engine, you'll need a 1/8 or 22mm clam (it's what I call it) wrench that fits on a socket wrench. Use with a 2 or 3 inch extender.
7) Unplug it from the top and feed the new sensor down the firewall.
8) Screw the new sensor on.
9) Close the center cover on top of the engine.
10) Use your OBD code reader to erase the code.
11) Give it a good test drive to make sure the code doesn't reappear.

2004 X5 3.0 Power Steering Pump R&R

1) Remove oil from Reservoir, I used a large syringe.
2) Remove the two clamps and remove reservoir, have a catch pan as there will be fluid coming out. I plugged the hoses with paper towels bunched.
3) Remove the fan, I use a 1-1/4" wrench.
4) Remove the Air Cleaner and MAF with hose at the side of the engine, this will give you more room.
5) Remove the Alternator, I didn't but this will give you more room to work.
6) Remove the belt by using a torx bit on the belt tensioner
7) Remove the two bolts (13mm) holding the front of the power steering assembly.
8) Remove the 13mm short bolt on the bottom of the assembly, this was a very tight fit.
9) Remove the large hose bolt using a 17mm wrench, catch can as there will be more fluid.
10) Remove the clamp off the smaller hose.
11) You should now be able to slide the assembly from the top, reverse order to install.