Explained: When to Change Your Timing Belt

Have you ever wondered just how often you should change your vehicle’s timing belt or chain to make sure your engine is happy and running reliably? 

Your car’s engine is a pretty complex bit of machinery that needs everything to be working together, at the right time. 

This is where a timing belt or a timing chain steps into the equation - but what exactly is a timing belt and what are the symptoms of an old one in need of replacement?

Let’s take a closer look at what a timing belt does, how to diagnose signs of an old one, when to change it and how much you can expect to fork out when it’s time to change your old timing belt.

What is a Timing Belt? 

A timing belt is a crucial component in a vehicle's engine, responsible for synchronising the rotation of the crankshaft and the camshaft.

It ensures that the engine's valves open and close at the correct times with the position of the pistons. This is essential for a smooth-running, efficient and reliable engine. 

In plain English, the timing belt keeps a bunch of important things spinning at the right time.

In many vehicles, a timing chain is used over a timing belt, which, thanks to its metal construction, proves a more durable option. 

Your vehicle’s engine runs on fast and precise rotations which, if it’s not running with correct timing, can raise many mechanical issues. 

What are the Signs of a Worn Timing Belt or Chain in Need of Replacement? 

The most common signs that your vehicle’s timing belt or chain needs to be replaced are as follows: 

• Reduced power when accelerating

• Engine misfires and ticking sounds

• An irregular, rough idle

• Engine refuses to start

• Excess exhaust smoke

• Engine light on the dashboard

• Oil leaks

• Visible cracks and frays in the belt 

What are the Mechanical Risks of an Old or Failing Timing Belt? 

If a vehicle’s timing belt or chain becomes old, worn, or breaks entirely, it can lead to a variety of mechanical issues.

Engine Misfire & Poor Engine Performance: If the timing belt is not functioning properly, the timing of the engine's valve operation will be off. This can cause misfires, loss of power, rough idling and overall poor engine performance.

Bent Valves: A broken timing belt can cause the pistons to collide with the valves, leading to bent or broken valves. This can result in expensive repairs and possibly engine replacement.

Engine Failure: If the timing belt breaks completely, the engine will stop running. In many cases, this leads to catastrophic damage from internal damage.

Increased Repair Costs: A failed timing belt can cause extensive damage to the engine, resulting in costly repairs. Replacing a timing belt before it fails is much less expensive than fixing the damage caused by a broken one.

Overheating: An old or worn timing belt can cause the engine to overheat, as it may affect the water pump, which is often driven by the timing belt. An overheating engine can lead to more severe damage, such as a warped cylinder head or blown head gasket. 

How Often Should You Change Your Timing Belt or Chain? 

The best answer to the question of how often you should be changing your timing belt or chain is simple, but it does change depending on the vehicle make and engine. 

Your vehicle’s manufacturer will outline replacement intervals for the timing belt, which is the best way to judge how often you’ll need to replace it. 

Replacement intervals for a timing belt are typically due every 100,000km. 

A timing chain - with its metal construction - is more durable and requires replacing every 150,000 - 200,000km. 

It’s worth noting, though, that some vehicles may require more frequent replacements of the timing belt while others may be far longer than what we’ve outlined. 

The best way to judge how often you should change the timing belt or chain is to refer to the vehicle’s logbook servicing schedule which outlines the manufacturer’s recommended intervals between replacements. 

How Much Does it Cost to Replace a Timing Belt or Chain? 

The cost of replacing a timing belt or chain in your vehicle varies dramatically depending on the vehicle and engine complexity. 

In some cases, a mechanic can get the job done in a couple of hours, while more complex engines can take up to six hours. 

It really depends on just how easily a mechanic can access the belt or chain which, for some vehicles, is an easy task while others, depending on the engine layout and positioning, can be a bit of a pain to access. 

In the most simple, straightforward replacement jobs, you might be paying between $400 - $600, while common replacement costs for a timing belt can total $1,000 for larger, more time-consuming engines. 

In the case of a timing chain, which often requires more work to access, you might be paying anywhere between $1,000 - $2,000, depending on the vehicle. 

Timing belt and chain replacements can prove costly because of the labour involved, which requires a mechanic to strip parts of the engine, replace the belt or chain and ensure the engine is set with the correct timing. 

Some vehicles are far easier to work on than others, hence the significant price difference for replacing an engine’s timing belt or chain. 

While it’s not a cheap job, replacing a timing belt or chain is far more cost-effective than replacing major engine components or buying a new engine altogether. 

Remember to keep your vehicle serviced at the correct intervals and follow all replacement and maintenance advice outlined in the logbook. 

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