My friend has a 2000 MB E320 Wagon with 54K miles on the 3.2L V6. He takes it to Jiffy Lube for oil and filter changes. The oil used is Mobil 1. His question is: What is the best filter to use? My question is: What weight M1 should he be using. I lean toward 10w30 summer and 5w30 winter. What OCI? The owner's manual suggests 10k?! This car is operated in the midlands of SC,ie, hot summers and mild winters.