What is a timing belt?

airdrie timing belt

Most internal combustion engines utilize a similar design, with a crankshaft at the bottom, and a camshaft above it. Both of these shafts spin, with the crankshaft being connected to the pistons; rotating as the pistons move up and down. The camshaft uses a series of lobes to open and close the valves, which let air in and out of your engine.

Since it’s crucial that the valves open and close at the correct time, the crankshaft and camshaft are connected by a timing belt, or timing chain. If this valve timing is not correct, the engine will perform poorly – or worse, may damage itself.

If your car is equipped with a timing belt, it is the single most important maintenance item on your vehicle.

When does a timing belt need to be replaced?

broken timing belt
Here’s why timing belts need to be replaced based on mileage: a failed belt will often look totally fine; except where it broke!

Your timing belt is usually very difficult to inspect, as it’s located inside your engine, underneath the timing cover. Even when the timing belt is easy to access, a visual inspection often won’t reveal if a timing belt is ready to fail. For this reason, a timing belt needs to be replaced based on mileage alone. Most car manufacturers recommend a replacement interval of between 100,000 and 160,000 km. This means that the belt must be replaced at 100,000 km; then at 200,000 km; then 300,000 km, and so on.

Your timing belt replacement interval will also be listed in the maintenance section of your owner’s manual. Don’t have a manual? Give us a shout, and we’ll look up the recommended service interval for you.

What happens when a timing belt fails?

timing belt damage
Here’s an example of engine damage from a broken timing belt: one of the valves in this engine came into contact with a piston; broke off; and was pummeled into the cylinder head.

A timing belt that is past its expiry date will eventually break. A broken timing belt is never a good situation; one that we wouldn’t wish on any Airdrie driver. Besides causing an inconvenient break-down, a broken timing belt can cause considerable damage to the engine. This is because most modern engines use an interference head design, where the pistons can actually contact the valves if the valve timing is not correct. This usually results in thousands of dollars of engine damage in the form of bent valves; broken pistons; etc.

Repairing the damage that results from a broken timing belt can sometimes cost more than the vehicle is worth; instantly rendering your vehicle almost worthless. The only way to avoid this situation is to replace your timing belt on time, every time.

Signs of a bad timing belt:

inspect timing belt
Going inside your engine: Through the spark plug hole, we are using a borescope to examine the top of a piston for signs of damage.

Most failing or worn-out timing belts give no warning whatsoever before they break. A completely broken timing belt will usually result in a no-start condition, with an engine that cranks over quicker than normal, and sounds differently while cranking. If your timing belt fails while driving, the engine will stall or shut off suddenly, and will not re-start.

Any squealing, rattling or other abnormal noises from the front (where the accessory belts are) side of your engine may indicate a problem developing under your timing cover. Any fluid leaks at the front of the engine could also signal a failing water pump or other issues that could lead to a broken timing belt.

When we suspect there may be internal engine damage as a result of a broken timing belt, we have a few tricks up our sleeves to know for sure. One of them involves using a borescope – which is a tiny camera on a flexible lead – to look inside the cylinders of the engine. This allows us to give you a better idea what the repairs will cost, without spending hours disassembling your engine.

Replacing your timing belt:

A timing belt replacement is a fairly labour-intensive job; usually taking between 3 and 8 hours depending on the vehicle. While the repair usually isn’t particularly challenging for a properly-trained and experienced technician, there are certainly several steps where a minor mistake could lead to major engine damage! For this reason, we do not consider a timing belt replacement to be a “do it yourself” repair; you should seek the assistance of a professional.

We feel that My Garage is your best choice for a high quality timing belt service in Airdrie, at a fair price. As with all of our work, you can feel confident that we will complete the job with care, and back the repair with Airdrie’s best parts and labour warranty.

Doing the complete job:

timing belt water pump
Here’s a timing belt replacement we completed recently. Note the new belt; water pump; tensioner; and two idler pulleys.

Along with the timing belt, there are several other components that should be replaced at the same time. This includes the water pump (if it is driven by the timing belt); the timing belt tensioner; and any other pullies or moving parts underneath the timing cover. We usually install a timing belt component kit that includes all of the necessary parts.

Since a failed water pump or pulley can often result in the same catastrophic engine damage as a failed timing belt, replacement of these other parts help guarantee that everything under your timing cover is capable of lasting another 100,000 km or more.

With the carefully-selected new parts installed, we meticulously reassemble your engine, then top off your high quality repair by flushing your cooling system and filling it with genuine OEM antifreeze/coolant. After a quick test drive by one of our caring technicians, your vehicle is ready for another 100,000+ trouble-free kilometers of driving!

Does my car have a timing belt?

The good news for motorists is that timing belts are being used less and less these days. Because of consumer concerns over the extra maintenance involved with replacing them, plus the damage that can result if the belt breaks, manufacturers are now moving towards the use of a timing chain in most applications. While a timing chain does offer some disadvantages vs a timing belt, a timing chain is usually maintenance-free and often outlasts the engine.


Are you wondering if your vehicle has a timing belt? Curious about what a timing belt replacement costs? Please feel free to get in touch with us any time! We’ll be happy to answer any questions you may have.