What is a Timing Belt?

That is a question we hear a lot! The team at Auto Stop has put together some information below to help answer some Frequently Asked Questions about Timing Belts:

• What is a timing belt? What does a timing belt do? A timing belt is a reinforced belt that connects the upper and lower half of an engine. The upper half of an engine (Cylinder Head, Valves Camshaft, and other components) must work exactly in time with the lower half of the engine (Engine block, Crankshaft, Pistons etc) to produce the power needed to propel a vehicle. When belts get older or have high mileage they can stretch and even break. The best way to prevent this is to replace your timing belt at the time or mileage recommended by the vehicles manufacturer.
• Do all cars have a timing belt? No, many cars have a timing chain instead of a timing belt. A timing chain will last longer than timing belts on most cars, as long as you do your preventative maintenance. Oil changes are critical for these engines with timing chains and variable valve timing (VVT), but we will cover timing chains in another article.
• Should I change my timing belt? Yes absolutely. A Timing Belt plays a critical function in keeping your car running and if it breaks, it will not only leave you stranded but can also cause major damage to the internal parts of your engine.
• What happens when a timing belt breaks? When your timing belt breaks many things can happen, none of which are good. First off, your engine will stop running. This can be hazardous depending on your driving circumstances, as you would no longer have power steering or power brakes. If your car has what is called an interference engine, a timing belt that breaks can cause major internal engine damage resulting in a much higher repair bill than one that is replaced during routine maintenance before it breaks.
• What is an interference engine? An interference engine means that the clearance in an engine is so tight - if the top half of the engine (valves) falls out of sync with the lower half (pistons), these parts can hit (or interfere) with each other. This almost always results in damage to the pistons and valves, with the possibility of other damage to the cylinder head.
• How often should I replace my timing belt? Timing belt replacement varies by manufacturer and by engine. Most reputable shops and manufacturers recommend that you replace your timing belt between 60,000 and 110,000 miles OR 7-10 years. Your vehicle’s manual will have the recommended mileage for your specific vehicle.
• What is involved in replacing a timing belt? The timing belt is mounted on the front of the engine underneath a timing cover and behind engine accessories such as Serpentine Belts and Tensioners, Alternator, Power Steering Pump, AC Compressor, Crankshaft pulley etc. Many times the timing belt replacement requires the removal of engine mounts and lifting up of the engine. If the engine faces forward in the engine compartment, the radiator and radiator fan may also need to be disassembled. In many cases you may have to remove the water pump and - fun fact - the timing belt actually runs the water pump in some vehicles.
• How much does a timing belt cost? Why does a timing belt cost so much? The cost of a timing belt can vary widely depending on many factors including the position of the engine in the engine compartment, what components have to be removed, how much clearance there is between the body of the car and the front of the engine. Other factors can include the number of accessories including idler pulleys, tensioners, camshaft and crankshaft seals that are recommended or need to be replaced.
• Should I replace my water pump with my timing belt? Water pumps are a common repair item and it usually makes sense to replace them when you are replacing the timing belt. In some cases the timing belt actually runs the water pump so there is no extra labor involved when to do it alongside the timing belt. In some cars the water pump is run by the drive or serpentine belt but, in almost every case, it would save you a lot of money to do these parts at the same time while everything is disassembled.
• When will my Timing Belt Break? That is a great question and it is very hard to answer. The best answer is that there is no way to know and that is why it is important to replace the timing belt when the manufacturer recommends it. Some years ago I drove a personal vehicle (Toyota, belt replacement due at 110K) to 170K before the timing belt broke as I too wanted an answer to that question. I had a friend around the same time who had a different model Toyota and their Timing Belt broke at 59K just a few miles short of the recommended replacement interval of 60K. Luckily for them the car was under warranty as it ruined the engine.

The bottom line is that Timing Belts should be replaced at the time or mileage recommended by the manufacturer. If you are not sure when your timing belt was replaced we’ll be happy to research it for you. Schedule an appointment here.