motorcar vs winter rat

motorcar

noun
  • An enclosed passenger motor vehicle, a car, powered by an engine. 

  • A self-propelled railway vehicle 

winter rat

noun
  • An old, unattractive automobile, purchased for little money, to be driven during brutal Great Lakes winters while the owner's "good" car remains garaged and protected from corrosive road salt for the season. 

How often have the words motorcar and winter rat occurred in a corpus of books? (source: Google Ngram Viewer )