Since the inception of the internal combustion engine, one constant has remained – they all have a timing chain or timing belt. Most higher-displacement engines have a timing chain as opposed to a timing belt. The chain is located in the front of the motor and is attached to a set of gears and pulleys that power multiple mechanical components, including the crankshaft and camshaft. In order for your engine to fire, the timing chain must smoothly rotate around the gears without hesitation. Although the timing chain is made out of metal, it is subject to wear and tear and may break if not replaced as recommended by the factory.
The timing chain is comprised of a series of links in the chain – similar to those found on a bicycle chain. The links move on the toothed sprockets which are located on the ends of the crankshaft and camshaft, and are responsible for opening and closing valves in the cylinder head and moving pistons and connecting rods in the combustion chamber. The timing chain can start to stretch and wear over time, which will cause the engine's timing to be inaccurate and cause a few warning signs.
Listed below are a few of the symptoms of a worn out timing chain. If you notice any of these warning signs, it's advised for you to contact a local mechanic as soon as possible, so they can diagnose the exact cause and make appropriate repairs as needed.
1. Engine misfires
There are two ways to achieve valve timing in a combustion engine. The first is the two-gear method, which includes the crankshaft to camshaft gear direct connection. This is the method used in most types of heavy equipment and big trucks. The timing chain method is more common with consumer vehicles and high performance engines. Over a period of time, the timing chain can stretch, which can cause the chain to skip a gear on the cam or crank shaft. This results in the engine’s timing to fall out of calibration and often results in a misfire.
If this situation occurs, it's likely that the timing chain is damaged and needs to be replaced as soon as possible. If the timing chain breaks, the loose metal rolling around inside the motor can lead to serious engine damage.
2. Metal shavings are found in the oil
It's recommended by all automotive manufacturers to change the engine oil and filter every 3,000 to 5,000 miles. The reason for this is that over time, oil begins to separate as it heats up and is exposed to natural solvents found in gasoline. If the timing chain begins to wear out, small metal pieces can break off the chain, and find their way into the oil pan. When you have your oil changed, and the mechanic tells you that there were small pieces of metal inside the oil as it drained or in the filter, it's a good indication that your timing chain is beginning to fail.
Metal shavings are also common with extensive wear with cylinder head valves, keepers, retainers and other cylinder head hardware. It's critical that if a mechanic or technician tells you that there is metal shaving in the oil that you contact a local ASE certified mechanic to inspect this and make appropriate repairs as soon as possible.
3. Engine rattles while idling
Unusual sounds are also a common warning sign that a problem exists inside your motor. Under normal conditions, the engine should have a consistent, smooth sound that indicates everything is running as it should. However, when the timing chain is loose, it may cause a vibration inside the motor and will be indicated by a rattling noise as the engine idles. Anytime you hear a rattle it means that something is loose and needs to be fixed before it breaks.
The timing chain is an integral part of any engine, and without it, your vehicle is rendered useless. If the timing chain breaks while you are driving, serious damage to your vehicle's engine is probable. The best way to reduce the potential of serious engine damage is to have a professional mechanic replace your timing chain if you notice any of these warning signs listed above. By being proactive and alert, you can save thousands of dollars and extend the life of your engine significantly.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Timing Chain and was authored by Timothy Charlet.