old car vs winter rat

old car

noun
  • worn-out car, automobile in poor operating condition 

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