Yes, Auto RX would be my choice. My '93 300CE hadn't had the oil filter changed in 50K. It was a solid black piece of sludge. The removal of the valve covers showed a horrible sight. After 10K and two Auto RX doses, it is as clean as a whistle, and runs a lot quieter.
Anziani
'93 300CE 181K
'95 E420 118K