DIY - E53 3.0 Oxygen Sensor Replacement

[heizervr6]

After a few thousand miles of intermittant CEL's coming and going it was finally time to replace the post-cat O2 sensors. These were replaced for the first time at 150K miles but I believe these may be a part of Inspection II around 100K miles - if it's not safety related, why replace these ahead of time is my thought.




Parts required for an '01 3.0 X5 (Bosch 15109):



First thing to do is get the vehicle up on the passenger side so that you have enough room to crawl under it. Please note that I do not accept any responsibility for injury, death, fire, swearing, etc. This repair is attempted/done at your own risk!

Getting the vehicle up on jackstands/ramps is best done the night before so that you can soak the O2 sensors with PB Blaster. I would soak them again the morning of the repair.
0

Tools I used for this repair are pictured below:

Torch, PB Blaster, 22mm O2 Sensor wrench, 3/8" in drive ratchet (with extension if possible (black part), 3" extension, 6" extension, 13mm ratcheting wrench, 10mm socket, snips (there may be a tie wrap you need to cut) and not pictured is a small flathead screwdriver.

1) Crawl underneath the X5 on the pass. side and loosen both 02 sensors (I didn't remove mine entirely as I wanted to do them one at a time so that they connected in the same place above on top of the engine). The oxygen sensor that is horizontal gave me the most trouble (the one on top of the pipe came right out) so I heated it up so that it was red hot and then put the 02 wrench on and first tried slightly tightening it before loosening it all the way. For the one that is horizontal you may need to bend the flange back a hair that surrounds the sensor (this is what I used the hammer for by hitting the socket and flattenng them somewhat so that the socket would grip better)


2) Once they've been loosened where you can remove them by hand move up top and start by removing the parts up top. In hindsight you could probably get away without removing the entire cabin filter assembly but I figured having the extra room wouldn't hurt. If you want to go this route, remove the upper rubber trim, remove the tray below the windshield by twisting the fasteners a quarter turn, loosen the two 13mm nuts (one is behind the windshield washer fluid container and the other for the positive battery lead).



3) Lift up the side plastic pieces next to the cabin filter assembly


4) Next pull forward on the cabin filter assembly. It should move right out if you wiggle it gently


5) Remove the engine cover (use a small flat head screw driver and a 10mm socket). Once this has been removed you'll see the two connectors for the rear 02 sensors sitting right on top



6) You can now disconnect the sensors up top (one at a time) using a small flathead screwdriver.

7) Move back down underneath the X5 and unclip the wires from the retainers (they'll slide out to the side)


8) Remove the 02 sensors from below and feed the new ones in up top keeping the caps on them until you get them into position. Once in position make sure that they have anti-seize on the threads (mine came like that from Bosch). Install and tighten.

That's pretty much it. Installation is the reverse of removal. Good luck!

[coloradox5]

The heater burnt out on one of my O2 sensors this week at 130k. I will replace both front sensors this weekend. Thanks for the DIY with photos.

[Elvis 3.0]

Great post. How long did it take to to do the job and did you get anything else done while you were at it?

Thanks!

[heizervr6]

Overall I would plan on 2-3 hours including setting up the vehicle and cleaning everything up. For me, what took the longest was getting the O2 wrench to properly "grab" the nut on the horizontal sensor due to the flange getting in the way. Once I flattened it, it was a matter of heating up the exhaust hot enough (glowing red) so that the seized sensor will come loose. If I had to do this over again I could probably do it in an 1-1.5 hours or so because knowing where the connectors are for the sensors is half the battle as I had no idea where they might be starting this repair (thought they were hidden behind the engine although that wouldn't have been typical for BMW since everything is normally so easy).

No, I didn't do anything else while I was doing this repair since there's really nothing else that gets affected/removed.

[heizervr6]

Originally Posted by coloradox5

The heater burnt out on one of my O2 sensors this week at 130k. I will replace both front sensors this weekend. Thanks for the DIY with photos.

You're welcome and if you're replacing the pre-cat ones that should be even easier since they're right up top on the pass. side. Good luck!

[Elvis 3.0]

Thanks!

[imalabil]

OK please help--I want to replace the pre-cat sensors on my 2002 3.0. Do I only need 2? What is the correct Bosch P/N?
The post cats probably have a much longer wire.
Bill

[StartX5]

imalabil, i bought precat Bosch O2 sensors from this ebay seller, part# 13477. $128 free shipping per pair and these O2 sensors are exactly 100% the same the OEM that i pulled out from my X5.
2PC BMW O2 Oxygen Sensor Set FRONT/UPSTREAM Genuine Bosch w/ OEM Plug E46/M54 02 | eBay

These precat O2 sensors took me 25-30 minutes to complete the job. There are 4 wires 1 black, 1 grey and 2 white, making sure you plug new sensors same position of the old sensors.

[StartX5]

My 2004 3.0i 2 precat O2 sensors are vertical position, and i did not have to remove anything except sensors plug before taking them out.

[imalabil]

DUHH! I should have read this post more throroughly, it is about POST-CAT sensors.

It looks like the pre-cats are mounted on the exhaust manifold, #1:

I have not seen a DIY for these, but from what you say it should be straigtforward. I'm fairly fearless with engine things after successfully changing the oil filter assm. gaskes WITHOUT removing the fan, but don't ask my comments on BMW's torx socket belt tensioner--what a PITA.

I'm assuming that although BMW would like me to buy and change post-cat sensors as well, that only the pre-cats really need it at 100k. Gong to do plugs and trans fluid as well.

Bill