If you’ve been putting off getting your timing belt replaced or haven’t had it checked in a while, you might want to schedule an appointment with your service advisor right away! If you’re not sure when to change your timing belt, be sure to check your owner’s manual for recommendations. Some of today’s vehicles have timing chains, which don’t typically need to be changed, but it’s always a good idea to familiarize yourself with your automobile’s manual for recommended maintenance.
The timing belt is separate from the serpentine belt present in many cars. The timing belt keeps the rotation of the crankshaft and the camshaft so the engine’s valves open and close at the right time. This makes sure the cylinders intake and exhaust strokes are timed just right to keep your combustion engine combusting. In some engines the belt may also control important parts such as the water pump and oil pump.
The belt itself is made of flexible rubber-like materials like polyurethane or neoprene and has notches like “teeth” that fit into a gear. Over time the heat of the engine, oil, dust and dirt cause the belt to start to break down. It may lose notch integrity which will affect the performance of the engine because the drive cog will slip. The belt may also begin to fray, which will also cause performance issues and it may ultimately fail. The belt is made using high-tensile fibers inside so breaking is rare, but it can become too loose to work correctly.
Timing configurations of engines are typically one of two types: interference and non-interference. If your engine is an interference type and the belt breaks, chances are there’s going to be trouble. In an interference engine the valve and piston stroke take up the same space in the cylinder. Basically the timing belt keeps these two from crashing into each other, but if it snaps they’ll meet rather quickly and violently. Bent valves, cylinder head damage, camshaft damage and piston and cylinder wall damage are all possible if the belt snaps in an interference engine. If the engine is a non-interference engine you will be left stranded, but damage may be minimal.
Either way, it makes sense to change your timing belt when it’s time and keep tabs on belt age. Also it’s not uncommon for tensioners to go bad, so they may need to be replaced and if the belt runs the water pump a mechanic may recommend replacing it at the same time to avoid high labor costs down the road for you.