I too thought that was a gas engine only set up of an early vintage. You might consider posting this problem in the vintage section of the site as well. It also was mounted horizontal as well. I never owned a 115 diesel.

Or is it basically the later diesel filter set up just mounted lower? Well since it has O rings in there it is not like the gas engine oil filter setup. After some thought it possibly is just the same type filter housing mounted in a different location on the block.

I guess I still learn something every day. This model in diesel was really scarce even when new in my current area of the country. At the time the 114 gas models sold fairly well. I saw no visual difference between the 114 and 115 models.

Anyways it probably still is just the o rings. A pretty easy fix.

Still there was a 114 coupe with this engine in it sold used locally about ten years ago that sounded factory. Special order I wondered or converted?