bought the car in early 2003 from south carolina dealer and don't know when they installed. Pulled the battery today as it wouldn't hold a charge and saw it's a Motorcraft BXT-24..tested tough series. Amazing to me for a battery in AZ to last this long, The battery has the 3 yr free replacement and 48 month guarantee and so nothing unusual about that but it lasted past the 4 yr period. It would cost 99 plus tx to replace, tho.