motor oil

Most recent Mercedes models require synthetic oil to be used in the engines because of the protection it provides and so their maintenance reminder system works properly. I can't remember the specific oil weight you need but your owner's manual should specify that in the maintenance section. hope this helps

Year: 2007 Make: Mercedes-Benz Model: GL450 Engine Type: 8cyl. 4.6Liter Naturally Aspirated Mobil 1 0W-40 A fully synthetic motor oil, Mobil 1 0W-40 with SuperSyn Technology exceeds industry standards and the major leading builder requirements, enabling the product to keep performing well after conventional oils cannot. Mobil 1 is recommended by leading car manufacturers as initial fill. This is from mobile one's site

European Formula Synthetic Mobil 0W-40 . You can find it in Walmart SuperCenter...

Mobil 1 5W-40 Full Synthetic Turbo Diesel Truck is what I use and what the manufacturer recommends.