The chatty mechanics on NPR's "Car Talk" are pulling in to the garage.Tom and Ray Magliozzi said Friday they will stop making new episodes of their comic auto advice show at the end of September, 25 years after "Car Talk" began in Boston. The show airs every Saturday morning and is National Public Radio's most popular program.Older brother Tom is 74 years old and the brothers say it's time to stop and smell the cappuccino."Car Talk" isn't disappearing, however. NPR says repurposed episodes will continue to air every week with material culled from the show's archives.