Breaking in a new vehicle is really about the engine. The break-in — or mechanical run-in — period is designed to begin to wear the engine evenly and smoothly with low, consistent pressure, normal operating temperature and smoothly flowing oil. The goal is to get the engine's piston rings, which expand, contract and flex, to seat properly on the cylinder walls. If there are imperfections in the pistons or the cylinder walls from the manufacturing process, working the engine too hard and too soon can wear down those imperfections too quickly. That leads to "hot spots" within the engine's cylinders, which can cause problems in the years to come. … [Read more...] about Do You Have to ‘Break In’ a New Car?