I noticed a bit of oil in the O2 sensor connectors when I replaced them, yet didn't think much of it as it was only a small amount, cleaned them and installed.
My car has been needing < 1L of oil per 15K kms, nothing major, yet enough that I wanted to find the source.
Looked into other oil leaks on the W203 and saw the cam magnet sensors have leaked on the M111 causing oil to get into the harness.
I checked, and there's oil in the cam magnet sensors on my M271.
Luckily there no oil on the MAF sensor, or ECU connectors, so the problem might be isolated unlike the disaster it is on the M111 that ruins the ECU and requires the entire wire harness to need replacing.
Can someone do me a favor:
- pop the connectors off and look to see if there's oil on them.
- the magnets are circled in orange in this pic: