NHTSA Complaint #11469622 — 2005 MERCEDES BENZ SLK350

A few days after a scheduled service visit at a local Mercedes-Benz (MB) dealer I noticed a creaking sound coming from the rear of my 2005 SLK350 that continued to get louder as time went by. I scheduled another appointment for post-inspection and I received the unfortunate news that corrosion of the subframe had resulted in a critical fracture rendering the vehicle unsafe to drive and that I was actually lucky to have not been involved in an accident from the mechanical failure. It is clear from the undercarriage photos that corrosion was localized to subframe junctions where other areas/parts in the vicinity did not experience debilitating fracture damage. I was surprised that a recently-serviced vehicle was now deemed unsafe to drive and required an entire rear subframe replacement. After some further investigation online (via forums, etc.) this appears to be a prominent issue with the R171 generation of rear subframes where corrosion protection was not applied to the steel subframe interior during manufacturing, which results in corrosion from the inside out, and thus by the time the problem is visually evident it is much too late from a life safety standpoint.