The Collaborative International Dictionary of English v.0.48:

Service station \Serv"ice station\
   a business where automobiles may be serviced and repaired,
   usually also having a gasoline vending apparatus, in which
   case it is also called a gas station or gasoline station.
   Facilities for repair of automobiles but without a gasoline
   dispensing function are commonly called repair shops.
   [PJC]

WordNet (r) 3.0 (2006):

service station
    n 1: a station where gasoline and oil are sold and facilities
         are available for repairing or maintaining automobiles