Late last week, Ford Motor Company issued Technical Service Bulletin 11-7-7 regarding unapproved modifications to the 5.0-liter engines found in Mustang GT’s and Ford F-150 pickup trucks. Technical Service Bulletins are used to communicate service, repair and warranty information to the company’s dealers and their service operations.

In this case, the communication centers on modifications to the engine and how they may impact vehicle operations.

Specifically, the issue as stated in the Bulletin is that “Some 2011 F-150 and 2011-2012 Mustang vehicles equipped with 5.0L engine may have unauthorized modifications to the powertrain hardware and/or calibration which may result in exceeding component design limits. Such modifications could cause damage to the powertrain and/or void the factory powertrain warranty.”

Clearly, Ford has seen enough instances of damaged components that it feels a consistent evaluation procedure is required across its network of dealers. This may be a result of cases where improper procedures have been used at the dealer level to initiate warranty denial where modifications are involved.

Such issues are governed by federal law, specifically the Magnuson-Moss Warranty Act of 1975. The SEMA Action Network offers this guidance in application of the Act. “With regard to aftermarket parts, the spirit of the law is that warranty coverage cannot be denied simply because such parts are present on the vehicle, or have been used. The warranty coverage can be denied only if the aftermarket part caused the malfunction or damage for which warranty coverage is sought.”

The company’s action in releasing this TSB may signal a tightening of warranty enforcement on issues involving modifications, but equally or more likely are driven by a need for consistency in handling such issues at the dealership level. You can download a PDF of the TSB document here at The Mustang Source.