O2 sensor help? 535i

[InfernoM3]

Anyone with a 535i have some advice. I heard it was harder than it seemed with this car and might need to drop the exhaust? Also I've heard I may need special joint tools? Wht are they and where can I get them. if its gonna be a big fuss I may just let me mechanic do it. Would like to save the money though.

[GS535i]

Search ebay for Bosch sensors - you can get a 4-wire as low as $25, but here's a BIN @ $45 http://cgi.ebay.com/ebaymotors/ws/eB...957708597&rd=1.
Remove the current sensor, cut and solder the wires to length reusing the connector and following the colour code (2 white, a grey & a black -use heat shrink over each joint) - and install. The screw apart connector is just above the oil sump on the drivers (left) side.
Sensors arrive with anti-seize lube , so do not add more. If the threads are in question, a $5 tap called a spark plug 'thread chaser' can be threaded in to clean them up.
If you trace the wire and can get a wrench in there ...

[Mobius]

I just replaced mine on my 535 a couple days ago. Despite the special O2 sensor socket, and a bevy of socket u-joints and extensions, I couldn't get it to break free.

I ended up dropping the exhaust so I could get a wrench on it. It was far more work than I wanted it to be - but, I had the time.