What oil type do I use? 2016 GL 450
My GL 550 has 223k miles and you can actually hear a difference in the engine rotating resonance after 3k miles. There is also a distinct smell associated with the oil when it comes time to change it b/c turbos share same oil. Get to know it. When changing oil filter element, look for any particles under and within filter after removal while fluid hot/warm. Let oil fully drain for 25min. Fill oil to precise top level, though better to have a bit less oil than more - refill to top level after driving 3-5 miles. Always change out the copper washer on the oil drain plug.








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