#timingbelt #carmanufacturersrecommendations #interferenceengine The answer to this question should be answered by one of our customers who came in last week. He came in and his car was 15,000 miles over by recommended manufacturers mileage to replace his timing belt. He opted to wait. 2 weeks later he gave us a call. He had been driving on the freeway and the car quit running. Due to him waiting he risked causing engine damage to the cylinder head. This is called an Interference Engine. This is a type of engine in which one or more valves in the fully open position extends into any area that the piston may travel into. This kind of repair is quite costly and significantly more than he would have paid to just replace the timing belt.