I have not looked yet but can someone tell me the location of the O2 sensors in my 1998 740 il. Also can you clean these guys and get them to work again

You have 2 in front of the cats and 2 in the rear of them, the cats should be after the transmission under the car.

Here are some instructions on how to replace them,
http://www.bmwtips.com/tipsntricks/Exhaust/O2sensor.htm

http://www.bmwtips.com/tipsntricks/Exhaust/O2sensor_files/o2sensor1a.jpg

you might also find the online parts database an invaluable website to add to your favorites folder: www.realoem.com/bmw/select.do

The exploded diagrams and part number index can be used for multiple purposes. For example, the diagram below..item #8 is 02 sensor and #7 is the regulating probe.

http://www.realoem.com/bmw/diagrams/f/o/194.png

And www.autohauseaz.com has pretty good prices.

Hey Guys,

Which side is bank one and which is Bank two? or how are they set up on the 98' 740il?