02 sensor headache
 

I bought an 03 X5 (3.0) about a month ago and the my check engine light is on. Before I bought it, I brought it to Autozone and they said it's an 02 sensor, Bank 2, Sensor 2.

I figured no big deal. Got a new one and now I'm under the vehicle and ...hating my life. Wire to the sensor is cut, but, no big deal. Previous owner probably doing what I would've done. I put a bunch of PB Blaster on it, gave it a few raps with a hammer & screwdriver at the base of it where it threads into exhaust. My 7/8" deep socket isn't deep enough, so I'm using my 02 sensor tool, but, the hex-bolt is stripping/stripped and I can't get a good bit on the sensor. Tried using a propane torch, but, didn't go too nuts; didn't want to overheat anything nearby.

Ofcourse there is no easy access to this sensor. It looks like I may have to take it to a shop and have them drop the exhaust. The bolts look obscenely rusted so I don't like chances of getting them off in my driveway.

Anyone ever wrestled such a beast? Bummin' me out.
Thanks,

Jay

Yep.... I've always had to cut the wire off, then smash the ceramic part of the sensor with a hammer - but this then allows me to use a six point/impact socket plus a 2ft breaker bar on the nut...

Make sure you retap the thread before inserting the new sensor though (I ruined the threads on a new sensor by not doing this first last time I did it...) - an O2 sensor tap is only about £7 for a decent one in the UK...

On the basis that you'll have to go to a shop as it currently stands, then you may aswell give it a go...

Obviously use PB blaster/similar penetrant and as its an exhaust, it can take a fair amount of heat. I am about to change some more and will try using map gas and a blow torch - but the O2 sockets always seem to open up/slip when I use them to remove sensors. Only useful for tightening back up...

Smash the sensor body off and then use a six point socket and a breaker bar...

Yes, dropping is what's needed. Spring of this year we ended doing just as such

Thanks svvg and JSOTO. It's gonna take some work to drop the exhaust so I can even get a work working shot at the 02 sensor. Does no good to complain, but, ...man, it sure seems peculiar that BMW would position Bank 2 Sensor 2 "RIGHT THERE" with virtually no effective access to it. Knowing that they're a bear to get out... (Wanh:dunno:).

Time to start working on those exhaust bolts!!! Thanks all,

Jay

Spray some penetrating oil and deal with it another day. let the kreep oil work....

Bank 2 sensor 2 is the post cat sensor on the left side of the car, isn’t it? Easy access on the n62 4.8... - don't think you need to drop the exhaust???

I have a 3.0 (6 cyl) and the bank 2 sensor 2 is past cat on the passenger side, but, there is next to no room to get in at it. There is a metal bracket bolted into both pipes connecting to the "header pipes" and it is uniquely in the way; not to mention the pipes heading to the rear of the car off the header pipes - they're right in the way of getting at the 02 sensor.

I've got a 2001 3.0i

I just had those O2 sensors out and back in again, still working fine at 186k miles. I took them out as part of my top-end engine rebuild.

I had no problems at all using my O2 socket to get them out and back in (no cutting wires, etc), but this is a CA car. I bought my first car when I was living in Boston, so I know it is a little different out there.

But some info might help:

Those O2 sensors are screwed into a single piece that is the exhaust manifold + cat. If you think getting the O2 sensor out is tough, I promise you getting the exhaust manifold off the head will be tougher. It may have been the single toughest part of the rebuild. So there may not be much benefit to thinking about removing that.

Working back from that point though, it's pretty easy (with no rust). I ended up needing to remove pretty much the entire exhaust except for the driver's side rear muffler. Pretty easy, although it sounds like a lot. I did it to get clearance for removing and carefully reinstalling the exhaust manifolds.

So yes, you might get more working room by removing part of the exhaust from the O2 sensor on back. But don't plan on removing the exhaust manifolds.

I also disconnected the sway bar (roll bar, anti-roll bar, stabilizer bar) links and the sway bar bushings (required removing the stiffening plate) - did all that for just a little extra room to extract and reinstall the exhaust manifolds. Not sure if it will help on the O2 sensors, but was pretty easy for me, and I know sometimes doing a lot of little easy things can make the one really impossible thing possible.

Removing those things should help, as long as removing them is not too difficult.

In case it is not clear, that bracket you mention is just a loose piece held in with the bolts that clamp the exhaust to the exhaust manifolds / cats. So undo those bolts, and the clamp can come right off. Don't forget to put it back on when you're done. You should get a little more maneuvering with that stuff off.

Thanks. Yeah, I have no intention of taking off the exhaust manifolds. I just cant get at the sensor with any room to work and since the previous owner stripped the base of the sensor, I am going to ...need a lot of room to work.

Here's a video of the DIY when I did mine. Shown on our 2005 3.0i X5

https://www.youtube.com/watch?v=IN6_HxsKcRk

I just removed and installed my O2 2-2 last night. Jacked up the corner of the car a little and used a rug to climb under. My O2 socket has an 8-point hole to work with 1/2" extension every 45°

Here's the trick: you need to use a wobble extension and come below the pipe. You can get plenty of torque on it.

When I first removed it I didn't even need to PB blast just 100-120 ft·lb of torque with 18" breaker bar.

On one of the two I used a hammer on the crow foot but think that was 1-2 (right side) also not terrible amount of force but I did break the ceramic off to make more room for the tool.

There is a vibration damper blocking a lot of view take that off so you can see what you are doing.


Sent from my iPhone using Tapatalk Pro

https://uploads.tapatalk-cdn.com/201...e66ff0ade5.jpg

Here's a photo of me using my "Dr Seuss" ratchet to clean out the threads on sensor 1-2 (you can see the vertical 2-2 in the back)

Thanks all. I guess not all 02 sensors are created equal. As mentioned, the previous owner of my X5 did a good job of stripping the "bolt heat" at the base of the sensor. After multiple PB blasting and torching and hammering and cutting the top off etc. I finally brought it to a mechanic and for $70 I'm a happy man.

:thumbup:

Sometimes it doesn't pay to DIY.

Changed all four of my O2 sensors since they'd never been changed. No codes or other issues, but after reading the recommended service interval for them was 100,000 miles and I was at 220,000, I thought it would be a good idea. After reading of everyone's woes I was expecting the worst. Hit them with PB blaster the night before. They came right out. Toughest part feeding the wires from the downstream sensors up to the top of the engine.

Some of us are lucky; I guess. (Or maybe I forgot how to un-stuck bolts/sensors). I've changed about 8 over the years and never had as much challenge as this one. Rounded off "bolt head", tucked up behind pipes, .... Hopefully any future ones will be as easy as yours. Congrats

:thumbup:

I cut the wires and used the old sensor wires as a fish tape to pull up the new connector. Even so a challenge because the connector is so large.

For removing I put the crow foot socket on and if too tight to muscle out with the breaker bar I smack with a 3# hammer a couple times first and it's always released.

I used the old sensor wire as a fish tape for second one after running into trouble getting the first one run. I used an actual fish tape for the first one after having already pulled out the first.

Hah; clearly I should've just called you to come over and pop it out.

I PB Blasted
I used socket, breaker bar
I heated
I hit with hammer
I heated
I PB Blasted
I put tape inside the sensor removal tool
I hit with hammer
I heated 10 minutes, PB blasted, hit with hammer, used vice grips

Oh well.:dunno:

I live about 5-10 miles from Menlo Park (I'm in Redwood Shores). I've had no problems at all with the O2 sensors either (or just about any other fasteners on all of my other cars, vs. the stories I read on these forums). No PBBlaster, no prep, no 45* sockets (nice, BTW), no nothing special at all.

I will guess it is not just a matter of luck. The incredibly high taxes we pay out here are obviously used to fund a top secret government program to keep all automotive fasteners rust free. :dunno: You heard it here first. :thumbup: (seriously, it is the climate and good roads, no salt - which we do all pay for out here, directly or not)

I'd love to know how your mechanic got it out.

I completely disagree :rofl: . I pay HUGE taxes in ...Taxachusetts.

I assume my mechanic had better leverage with the vehicle up in the air and room to work. Probably better tools. Who knows. Like I said, I've changed many; some came out easy, some were tough, and this one I just couldn't get. Once that hex head got rounded off, it was kinda challenging. Oh well, I may just suck - glad it's done now.

$70 not terrible labor cost for TWO sensors. Didn't you say you did one yourself?

The best way to remove if it's stuck is a 22mm (7/8 in) : they are almost the same but slightly different use which fits better closed end wrench and hit with a hammer after pb blast or equivalent.

(Cut the wire to use closed end or I think you could fish the entire wire through)

It's key to get good grip before rounding and I suspect lots and lots of heat would release the rounded stuck one so some map gas or oxygen/acetylene.

I have to swap out a defective when new sensor. It's a clone but German made. One worked one didn't. I got no grief from the seller to get a swap just needed a pic of the serial #

HUGE TIP: Take a pic of serial number when installing any new part: twice in three years I had to send a photo of the serial number to get a replacement part and it's a lot easier when new and not installed (good example: fuel pump). The serial number is on the flat of the O2 sensor and completely unreadable once used for a few months.


Sent from my iPhone using Tapatalk Pro

:rofl::thumbup: The benefits of living where there's never any snow! Could also be the ridiculous taxes. Something special in the air?