The rubber bond in the harmonic balancer can decay, which causes the balancer to move and work its way toward the timing cover. If the balancer comes into contact with the timing cover while the engine is running, it will fracture and damage the cover and potentially other surrounding parts. The harmonic balancer should be inspected at every service.
Harmonic Balancer May Fail and Damage Timing Cover on Mercedes-Benz CLK430
Average mileage: 125,000 (125,000–125,000)
6 people reported this problem
1999 Mercedes-Benz CLK430 125,000 mi, Visitor
as stated above, balancer seperated and outer portion slid back towards engine and started machining into cover and block poor quality parts should be replaced for free by MB--IMHO