Let’s Talk Timing (Chains)

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Many drivers know they have either a timing belt or a timing chain, but they don’t often understand the difference between the two, especially since both parts function in the same way.

As your engine runs, the intake valves need to open up to allow air to enter the engine. These valves remain closed while the compressed air and fuel are ignited, which powers the pistons. Then, the exhaust valves open to release the exhaust. All these functions need to be timed very precisely for the engine to run well. This responsibility falls on the timing belt or chain, which ensures every function is synced up properly.

Aren’t Timing Chains Indestructible?

Although timing belts and chains have the same job, there are some important differences. Timing belts are made of a rugged compound, typically rubber with high-tensile fibers, and last an average of about 7–10 years. If your vehicle has a timing belt, the owner’s manual will include a schedule for replacing it.

Timing chains are made of metal and look very similar to the chains on a bicycle. If your vehicle has a timing chain, the owner’s manual may not have a specific replacement schedule listed—but that doesn’t mean that the timing chain is indestructible and doesn’t require attention.

Timing chains run on sprockets on the crankshaft and camshafts. Over time, the teeth on the sprockets can become worn or damaged. If you have a broken sprocket tooth, this can cause the timing chain to slip, and as a result, your engine won’t run as smoothly. If the timing is off enough, it can prevent your engine from running at all, or even cause engine damage.

In addition to these sprockets, there’s also a tensioner, which keeps the right amount of pressure on the timing chain. The tensioner keeps the chain taut, but also allows for enough slack to absorb the pulsations from the engine. Like the sprocket teeth, the tensioner can become worn out, which throws off the tension on the chain. The guide rails that keep the chain on the proper path can also become worn and require replacement.

The Bottom Line

Although timing chains are generally intended to last for the life of your vehicle, one or more of the timing chain system components will become worn at some point. When this happens, your engine won’t be able to perform within the manufacturer’s specifications. For this reason, it’s important to have your timing system inspected occasionally to ensure everything is in good condition and functioning as it should. Your service advisor can help you with recommendations for when the components need replacement and when to have your vehicle inspected for signs of timing system wear. And since timing chains are lubricated by the engine oil, performing regular oil changes is essential for keeping all the moving parts properly lubricated, reducing friction, and preventing wear.

For specific service recommendations for your vehicle, or to schedule an appointment, call EuroCar Service today at 206-527-8828. We see all European makes, including Audi, BMW, Land Rover, Mercedes, Mini-Cooper, Saab, Jaguar, Volkswagen, Volvo, Smart Car, and Fiat!