I have a 2002 ML320. I've put 30k kms on it. (Currently 98k kms on the odometer.) For the first oil change after I purchased it, I put in Amsoil AFL, which they are now calling mid-saps. (I realize the vehicle does not call for oil meeting MB 229.51, but I had some of this oil for another vehicle, so I used it.) I used an OEM synthetic oil filter. Also, not long after I purchased the vehicle, the rear main seal started leaking and eventually got bad enough to require replacement. I ran the AFL oil for two oil change intervals. For the most recent oil change that was done after the rear main seal was changed, I put in Amsoil EFM which they are calling full-saps. Initially, with the leaking rear main seal, I couldn't tell if the vehicle was using oil (as opposed to leaking it), but lately, with the real main seal fixed, it appears to be using oil, approximately 1 l per 1000 km, which in my opinion is excessive. Is it possible using AFL instead of EFM could have contributed to oil consumption?