The cost of replacing your timing belt varies from car to car, even location to location. Smaller BMW cars with smaller engines are generally less expensive than a larger BMW with a bigger engine. Metropolitan areas usually mean higher costs, too.

Belts themselves aren’t that expensive. The real cost is in the labor, because a lot of parts need to be disassembled to get to the belt. Shopping around to get a few quotes is your best bet to get the best deal, but you can expect to pay anywhere from $409 to $919 (including parts and labor).

Have a timing chain instead of a timing belt? Lucky you, because they can actually last the lifetime of your car.

For more information, read our article What is a timing belt?

Although timing belts are critical, there’s no need to replace them regularly –unless explicitly recommended in your BMW owner’s manual. Some automakers recommend changing a timing belt between 60,000 and 100,000, others don’t.

Many of today’s timing belts can go 100,000 miles or more without needing to be replaced. In fact, not all cars use a rubber timing belt. Some use a timing chain that can actually outlast the engine.

If your owner’s manual doesn’t have a recommended schedule, and you suspect something may be wrong, you can have a mechanic do a visual inspection, which includes removing the timing belt cover attached to the engine block. If your mechanic notices that your belt is cracked, frayed or worn down, then it’s time to replace your timing belt.

You don’t want to know. But if you must, it’s not good. There’s usually a lot of noise, and if you’re driving you won’t be for long. You’ll be stranded, and your engine will probably be damaged (metal components can actually break, hence all the noise). How much damage is anyone’s guess. Bottom line? Don’t let this happen.

A timing belt won’t make noise when it’s in good condition — aside from the usual noises that come with the symphony of moving parts of the typical internal combustion engine. However, when your timing belt starts to go, that’s another story.

Usually, but not always, a timing belt will make a high-pitched, squeaking or ticking noise before it fails. If you hear this type of noise coming from your engine, it’s best to have it checked out by a professional. Because if you let the noise go on for too long and your timing belt breaks, the result is an expensive headache you don’t need.

Depending on the vehicle, you either have a timing belt or a timing chain. Belts usually need to be replaced at some point of ownership whereas chains can last the lifetime of your car. So, for the sake of argument, let’s assume your BMW has a timing belt. Here are a few common symptoms of a timing belt gone bad:

• Rough idling or engine misfiring
• Car won’t start
• A high-pitched squeaking or ticking noise coming from the engine
• Loss of oil pressure
• Oil leak from the front of the engine
• Check engine light comes on

People usually discover a bad timing belt when it’s too late — and it breaks. You want to avoid this nightmare scenario all costs, because if you don’t, it’ll cost you big time. So, if you suspect you have a bad timing belt, the best thing to do is have it inspected by your mechanic as soon as you can.