Ted,

I replaced that rubber boot a few years ago when the old boot fell off and caused a drop in oil pressure. Keeping the crankcase full of oil kept the oil pressure up OK. I didn't know what caused the drop in oil ressure but I found out when I removed the lower oil pan for another reason and found the boot in the bottom of the pan. Then it was apparent why I had to keep a higher oil levelain the crankcase.

The rubber boot part was readily available from a MB dealer and didn't cost much. Sorry,
I don't remember the P/N and can't find it.

P E H