Irregular and premature tire wear can be caused by the front thrust link bushings cracking and causing excessive movement in the suspension. The thrust link bushings are fluid-filled (to help reduce vibration), so if they crack, they will leak oil.Google+
Car Problem Reports
Mercedes-Benz E320 CDI Tire Wear Caused By Worn Front Thrust Link Bushings
Mercedes-Benz E320 CDI Problem
Average Mileage: 148,000 mi (100,000 mi - 196,000 mi)
Visitor, 2005 Mercedes-Benz E320 CDI, 100,000 mi
The bushings became worn and I probably delayed replacing them longer than I should have; I definitely noticed increased tire wear.