exhaustgases

It seems no one knows how to change the hidden o ring on the oil filter cap assembly. No one ever does it on youtube, so does it just pull apart or is there some special secret to separating the parts?

device2

To be honest with you I use that extra O-ring for when the oil sensor leaks because it is the corresponding size for it. I have never seeing anyone change that supposed hidden O-ring in the filter housing assembly. I even tried to take the housing apart once at the stem (carefully because I didn't want to break it and buy a whole new assembly) and saw that there was no O-ring in the stem. Just the ones pointed out in the picture above. My only conclusion is that extra O-ring then is intended the sensor, which resides inside the oil pan. Since it does wear from heat and cooling cycles, meanwhile other folks just tend to toss out the "extra" O-ring.

exhaustgases

Any time you see a how to on youtube some one writes that you missed the o ring in the cap for the stem?? Since those parts are not made as a single unit they have to be separate parts and a way to take them apart???

Serndipity

exhaustgases...the are no hidden 0 rings on the oil filter spindle for the M112 or M113 engines. There are only 4, as shown by the red arrows in post #2.

Initially the recommended MB fleece filter only came with those four 0 rings. Subseqently, the filter kit added a 5th 0 ring. Additionally, 2 lines where marked on the filter.

That's because the same filter element was used on other MB engines, which either required fewer or more 0 rings on the spindle.

In summary.......on the aforementioned engines, the correct procedure is to:

-Use only the required four 0 rings, discarding the extra one.
-Make sure that the filter element is properly (i.e. fully) fitted on the spindle with only show 1 line showing.
-Make sure that the large 0 ring is in the proper grove and not up against the lip of the oil filter cap. If misfitted, you'll have an oil leak.
-Only use the MB fleece filters, or OEM (i.e. MANN HU718/5x). The cheaper paper filters are not up to par for FSS service and/or will likely crush when putting it on the spindle.