clunker vs winter rat

clunker

noun
  • A decrepit motor car. 

  • Anything which is in poor condition or of poor quality. 

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 clunker and winter rat occurred in a corpus of books? (source: Google Ngram Viewer )