Not difficult, the drain plug is a
. A standard torx will likely strip the plug. I replaced the crush washer but it could likely be reused so long as you don't go crazy tightening it. The filter housing has a drain plug (10mm hex) but I found it to be very slow and still pour out the sides when I removed the filter so I probably won't waste time with it again. If you aren't using a lift you'll need to remove the skid plates. Start with the front one, it has about a dozen 13mm bolts holding it on. The two front middle bolts are slotted so you can slide the plate back after removing the rest of the bolts and loosening those two. The mid skid plate only has about 6 bolts but is hooked at the front. You'll also need to remove 4 10mm bolts from the plastic cover behind it to fully release it. Both of these pieces are heavy so be careful. If you have a lift things are a bit simpler as you can simply let the middle plate hang once you release it. I overfilled the first time as I read the capacity wrong. In the workshop menu it would read the level in real time and with .1L precision. Told me there were 10L in the engine instead of 9.5L immediately but it took almost 10 days of driving before the "Reduce oil level" message was displayed. I simply removed the filter drain plug and allowed .5L to drain out. Next time I'll get the right amount to start with. Good to know the level sensor is accurate though since there is no dipstick. I used Motul's 8100 EFE 5w-30. It carries MB's 229.52 spec, also works in our ML, and can be had from Amazon for a reasonable price.
More good oil change references found below.
https://mbworld.org/forums/gls-class...ml#post8221975