o2 sensor location
 

i have a bmw x5 2004 3.0 .how do i know that my o2 sensor locate before or after the calt.... ?

You have 02 sensors before and after the Cat. the ones before the cat are on the left-side of the engine block/valve cover. the ones behind are underneath the car

And if you are planing on replacing the O2 yourself, get the O2 tool. It makes changing them very easy and its cheap. Like $20.00 or so. I did mine this weekend and it took about an hour for all four.

Hey which tool did you use?

I got it from bavauto.com. Its called the "oxygen sensor tool" $ 18.95.

Thanks. I'll check it out.

which o2 sensors did you use?

OEM Bosch sensors for me

What was your car doing when you changed your sensors? I have my checklight on and its talking about the sensor on the top of the engine that is easy to reach...i think thats what the dude said.