You are not required to purchase services and parts (such as replacing your car's air filter) from the automobile dealer in order to maintain the warranty on a new car or truck. According to the Magnuson-Moss Warranty Act, which became law in 1975, purchasing non-dealer or third-party parts and services (such as having Retro Lube replace your car's oil filter) does not invalidate a vehicle's warranty.

A detailed review of the Magnuson-Moss Warranty Act can be found on the USA government's Federal Trade Commission Web site.