Many part materials are exhaustively analyzed and tested by Ford during the vehicle development process to meet internal and external requirements for safety, quality, fuel economy, cost-of-ownership and breakthrough technologies. At Job 1 (first production assembly of a new model) for the 2005–2009 Mustang, specifications called for single-density polypropylene front and rear bumper isolators. However, as the vehicle had been tested and certified using a double-density polypropylene front bumper isolator, Ford maintained the use of that material until the vehicle could again be thoroughly tested and certified using the single-density polypropylene front bumper isolator.
From Job 1 until January 18, 2007, the double-density polypropylene bumper isolator was used for both vehicle manufacturing and service replacement. Upon completing testing and proving the single-density polypropylene front bumper isolator met all requirements and specifications, it went into vehicle production and was used for both vehicle manufacturing and service replacement. As both double-and single-density bumper isolators were proven forward- and backward-compatible, both were available for service replacement until stock of the double-density isolators was exhausted.
Ford said, “This chronology illustrates the lengths that Ford goes through to thoroughly test our Genuine Ford OEM Collision replacement parts as part of an entire system. These facts and Ford’s continuing concerns with the fit, finish, material composition and structural integrity of aftermarket collision parts reinforce Ford’s position that Genuine Ford Replacement Collision Parts are the right choice for consumers.
The carmaker concluded, “As the NSF testing speaks to material differences, it would have been more complete and meaningful if the aftermarket polystyrene isolator had also been tested and compared to the Genuine Ford polypropylene isolators.”
The statement refers to the relatively small difference between the single-and double-density polypropylene isolators tested by the ABPA as opposed to the more extreme difference between the OEM high density polypropylene isolators and the substitute aftermarket isolators made from polystyrene—the white “styrofoam” that coffee cups are made from.








