The rubber bond in the harmonic balancer can decay, which causes the balancer to move and work its way into the timing chain cover. If the balancer comes into contact with the timing cover while the engine is running, it will fracture and damage the timing case 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 CLK55 AMG
Average mileage: 84,250 (78,500–90,000)
8 people reported this problem
2003 Mercedes-Benz CLK55 AMG 78,500 mi, Visitor
Had to have the harmonic balancer replaced
2003 Mercedes-Benz CLK55 AMG 90,000 mi, Visitor
Balancer came off while driving, but belt stayed in contact with pulley as I was able to make it 3 miles home.