ushawk1

I bought an '03 C230K not too long ago, and Carmax claims they changed the oil. I don't trust them, so I changed it this past weekend. The oil that came out was blacker and thicker then anything I've ever seen. The filter was pure black. I put in a fresh Mann filter and some Mobil 1 0w40. I don't think there is any sludge in the motor (it has 37k on it) but is the M271 easily upset by not changing the oil, or by using some crap conventional 10w30 from WalMart? I would think that tight tolerances and a supercharger wouldn't like dirty bulk oil. The previous owner didn't have the car serviced at MB but a few times, so there is no telling how old the filter is, and where the oil came from. (Damn that Jiffy Lube....we used to not change cartridge filters, as we didn't have them in stock, and had to turn the cars around in 15 minutes)