I ran across some info. on the oil filter requirements for the MB's, that the OEM filters have a check valve in them. The reason being it holds the oil after shutdown to facilitate the quicker response on re-starts. Then it would get lubrication the the bearings etc. much better. My question is how can you tell or know if you didn't buy an OEM filter whether it has a check valve in it or not?? Would appreciate any help on this. I just noted the M103 in the title, because that is what I now own.