When To Replace Timing Belt
Timing belts have replaced timing chains on many of today's engines. Not to be confused with “V-belts” or “Serpentine belts”, which are located on the outside of the motor to drive accessories, timing belts perform a much more vital role.
The purpose of a timing belt is to provide a connection between the camshaft and crankshaft to ensure that the pistons and valves operate together in proper sequence. Timing belts have proven to be lighter, quieter and more efficient than chains, but those benefits come at a cost - they require more frequent replacement than chains.
Timing belts are used in two types of engines designated as "free-running" and "interference". If the timing belt breaks on a “free-running” design, the engine will stop and you will need a tow to the repair shop. There is enough clearance between the pistons and valves so no mechanical damage usually occurs. The installation of a new belt is usually all that is needed to get you back on the road.
If the timing belt breaks on an “interference engine”, mechanical engine damage will occur. Most commonly, the damage involves the pistons hitting open valves, resulting in the need for expensive repairs. In extreme cases, replacing the engine may be required.
Breakage is not the only reason to replace your timing belt. Looseness and wear can allow the timing belt to slip, resulting in very poor performance, a no-start condition, or engine damage.
Proper maintenance requires timing belt replacement at regular intervals – before it breaks or wears out. The manufacturers provide a replacement schedule and repair information for this critical component.