earlier this morning my wife called me while she was driving her ML and told me that she is getting a message in the tripometer reading "-2.0L" along with beeping, its come on twice. I cant seem to find any info of it anywhere on the web or in the manual, anybody have any clues?

Check the oil level.

yeah i was leaning towards that, had the wife top it off, ill have to check it tonight, the oil level has been coming on and off and ive been topping it off here and there. I used 0W40 in my last change based on what i found through the net, however when i spoke with my tech, he was saying it was too thin and recommended 5w30, any thoughts? There are visible leaks, and Ive already replaced the seals on the oil cooler and housing.