But the real danger lies not in the inconvenience of being stranded on the road. It is in the real possibility of severe engine damage, warn engineers from The Gates Rubber Company. However, an interference engine may allow the piston and the valve to collide. The least damage could be a bent valve. The most damage may be a hole in the piston, or damage to the head, or gouged cylinder heads, or worse yet, a completely ruined engine.
Most domestic cars are free-running.
Several notable exceptions are some models of the Chevy Spectrum and Chevette, Plymouth Colt, and the Pontiac LeMans and Sunbird. Most import cars, however, have higher compression engines, and are most likely to be the interference type. More than a dozen manufacturers, from Acura to Yugo, have produced this type of engine. Also, all diesel engines are interference. Rather than risk an expensive engine repair, Gates suggests car owners heed the advice of the auto manufacturers and most independent repair technicians.