Fiat Chrysler Automobiles NV on Tuesday logged a better-than-expected 1.7% increase in U.S. auto sales in August despite a calendar quirk and a tough year-over-year comparison, extending the auto maker's streak of sales gains to 65 months. More sales results from auto makers are due out later Tuesday, and overall U.S. sales are expected to cool in August as the impact of a later Labor Day masked an otherwise strong month of buying.