hzhang

Hi there
I have a 2004 525i and want to replace the oxygen sensors.
1) I checked online and found that not only they are expensive, but the 4 sensors are differently priced. Just curious why the two upstream ones are different and the downstream ones are different from each other.
2) there are some cheaper sensors (APwi brand) compared with Bosch or ntk. I am wondering anyone used those?
3) where is a good place to buy the sensor wrench?)

Thanks in advance. Any advise/comments are greatly appreciated.

HB

Only Bimmers

Hi HB,

The 2 pre-cat are really the ones you need to replace. Stick with OEM Bosch on these. As far as price, they are different lengths and the insulator is a different color so that is reason enough for them to stagger the price.

hzhang

Thanks, only bimmers

luigi524td

Has your car thrown codes that lead you to believe the O2 sensors need to be replaced? Generally these work until they don't. And they will "code" -- sometimes - meaning sometimes O2s are replaced but the codes persist because it was really something else that failed.

hzhang

thanks. No code yet. But according to the manual Bentley I need to replace the oxygen sensors at 120000 miles for e60 m54 engine. I figured sooner or later I will do this, why not now and follow the manual.

Thanks again.

Bimster530i

+1 Stick with Bosch/OEM O2s

Get a "crow's foot" style O2 sensor wrench. The ones that look like a deep socket with a split up the side for the cable usually don't fit the BMW O2 sensors.

Many auto parts stores have these wrenches in stock for ~$10.

hzhang

Thanks for the advise. I decided to buy both.
Appreciate your time.