Thanks for the post - I am getting ready to replace the front O2 sensor on my wife's '95 850 Turbo and your information has answered many of my questions! I was able to get the clip off of the sensor leads down underneath the car without breaking it. I removed the old sensor and reinstalled it; I wanted to see if it was stuck, and if the O2 sensor socket for my '80 245DL would fit (fits 7/8" and 22mm), which it did. I wasn't sure how the red cap worked; now I know, thanks to your post!

I was also wondering about replacing the wiring harness for contamination reasons; FCP Groton specifies on their website that the replacement is necessary for the 1997 and newer 850's only; I feel reasured, though, to have that information confirmed by your research.

I have a few questions:

1. How many more clips for the leads are there and where are they located?

2. Did you use a universal sensor, and if so, how did the splicing go?

Thanks again,
Bill