oil leak
 

A 2001 ml 320, if non synthetic oil is used, will that increase oil pressure and cause oil to seep from the top exposed o ring of the filter canister?
I used the dealer supplied oil filter & o rings, did not over tighten filter assy., did put required amount of oil in. Tightening the filter assy. any more now will cut the o ring. I used Castrol 10 w 30 oil. This is a gasoline engine. Thanks

The type oil used should have no effect on an oil leak. Why aren't you using synthetic Mobil 1 0W40 that MBUSA recommends for most engines of that vintage?

<< top exposed o ring of the filter canister >>

There is no exposed O-ring. If you can see an O-ring, you haven't put it in the right place. The oil filter cap torque is 25Nm, 18 ft lb. It should never have to be tightened any more than that, and it will never leak.