One problem related to other fuel system tank assembly has been reported for the 2008 Mercedes Benz CLK550. The most recently reported issues are listed below.
I purchased the vehicle used from a private party on 10/21/17 with 76,860 miles. I filled the tank with gas, parked it my garage, door closed. Next morning there a very strong odor of raw gas. A mercedes dealer confirmed through diagnostics and a smoke test that both sending units and seals were defective, and needed to be replaced.