Carmakers' rhymes with:
carmaker's, carmakers, carmaker's, carmakers, carmaker's, carmakers, automaker's, automakers, automakers', carmaker's, carmakers, chipmakers, dealmakers, dressmakers, drugmakers, filmmaker's, filmmakers, foodmaker's, foodmakers, haymakers, homemakers, kingmakers, lawmaker's, lawmakers, marketmakers, matchmakers, moneymakers, moviemakers, newsmakers, oddsmakers, pacemakers, peacemaker's, peacemakers, policymakers, printmakers, shoemakers, steelmaker's, steelmakers, toolmakers, toymakers, troublemakers
Carmakers' sounds like:
carmaker's, carmakers, crunchers