Symptoms of a Failing Timing Chain | Autance

The timing chain or timing belt (sometimes called a cambelt) is an essential part of every internal combustion engine. Sometimes…

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Symptoms of a Failing Timing Chain | Autance © Symptoms of a Failing Timing Chain | Autance

The timing chain or timing belt (sometimes called a cambelt) is an essential part of every internal combustion engine. Sometimes the job is done by a system of gears instead but there has to be some method of synchronizing the crankshaft rotation with the camshaft(s). This makes the valves of the engine open and close at the right time.

Timing chains were the norm for cars produced in the 1970s and 1980s but then timing belts took over. However, they have been more widely used in recent years as they are more durable than timing belts. A timing chain is a roller chain and you will find it at the front of the engine. Next to it are pulleys and gears which are connected to the mechanical components of the engine.

They are made up of a series of links, just like you see on a bicycle chain. There are toothed sprockets at the ends of the crankshaft and camshaft and the links locate into these. As the chain moves, it opens the valves and moves the pistons which are connected to the rods in the combustion chamber.

Chains are more hardwearing than belts but they too can wear out and they can break. As they stretch, the timing of the engine becomes inaccurate and this can produce some warning signs that you need to pick up on.

Here are the five main warning signs that your vehicle’s timing chain is failing. If you notice any of these signs, take your car to a qualified mechanic. They can find out what the problem is and carry out the necessary repairs.

Engine Misfiring and Lacking Power

When an engine misfires, it is a problem with the valve timing. So, how is this related to the timing chain? There are two ways in which the valve timing can be achieved. The first is found in heavy-duty machinery and in trucks. Here, there are two gears that make sure that the valves open when they should.

The other method is the timing chain method which is normally found in standard cars and in high-performance vehicles. However, it is possible for the timing chain to stretch with time. This means that the chain skips a gear either on the camshaft or on the crankshaft. The engine’s timing will be out of calibration and you hear the classic misfire sound. You may also notice that the engine is running poorly and when you try to accelerate, you lack power.

This is something that you need to get looked at right away. If the chain is stretched it is probably quite badly damaged and will need to be replaced soon. If you carry on driving the vehicle, the chain could break and the loose metal will cause serious damage to the engine.

Metal Shavings in the Engine Oil

This is something that will only be noticed when you have an oil change. This needs to be done either every 3,000 or every 5,000 miles. The oil filter should be changed at the same time. An oil change is needed because oil separates as it heats up and reacts with the natural solvents that are present in gas. It stops doing its job so well and does not lubricate and protect the engine.

When the timing chain wears out, small pieces of metal get broken off and end up in the oil. They will be clearly visible in the oil pan when the sump is emptied. Your mechanic will probably mention it to you and recommend what course of action you should take.

Don’t jump to this diagnosis yourself though because metal shavings in the oil can also be caused by worn cylinder head valves or other hardware related to this component.

Engine Failure

If the timing chain breaks as you are driving, the engine will stop and you will break down. If your car is parked up at your home and the chain is broken, the engine won’t be able to compress enough air to get it started.

This is not good news. If the chain broke whilst you were driving, it is likely that the pistons will be damaged because they will have had contact with the valves. The valves could also be bent and this can ruin the engine. A loose belt can jump around and can also flail around which is very likely to damage other parts of the engine.

This is definitely one scenario where prevention is better than cure. So, if your car won’t start or it breaks down as you are driving it is essential that you get it looked at right away.

Engine Light is Illuminated

The engine light can illuminate for several possible reasons. One reason is a failing timing chain. The computer in your car detects that something wrong with the way in which the engine is working.

When the timing chain is stretched, it makes the engine perform poorly and so the engine emissions are increased. This triggers the engine light to come on. A qualified mechanic will be able to use special software to detect a stored diagnostic trouble code. They will also visually examine the engine.

Rattling Noise When Idling

Listening to your engine is a good habit to develop! Unusual sounds are a reliable warning sign that something is going wrong. If all is well, your engine should make a smooth and consistent sound. However, when a timing chain is working its way loose, it causes vibration inside and this sounds like a rattling noise when the engine is idling. A rattle always indicates that something is loose and should always be investigated.

The timing chain is a vital part of your engine. It is one of the components that you can’t do without and when it fails it can do a lot of damage to the engine. Prevention is always better than cure so be vigilant for issues with your timing belt.


  1. Symptoms of a Bad or Failing Timing Chain – YourMechanic
  2. How Timing Belt Replacement Works – HowStuffWorks
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