If you have a car with more than 70,000 miles, there’s a secret risk you should think about. It’s a small part that wears out, and if it breaks before you fix it, it could kill your engine. We’re talking timing belt.

It’s a sad but common tale: someone drives down the road, the belt snaps. The car stops and won’t restart. A tow truck transports the car to the auto repair shop, and the driver finds it costs $2000 or more to rebuild the engine. It’s normal because it happens to many people; it’s sad because it’s preventive.

What’s the timing belt?

It’s a thin, toothed belt that connects camshaft to crankshaft, controlling valve timing. It’s durable and takes a lot of violence, but it won’t last forever. If it fails, the pistons immediately start rubbing against open valves, destroying the engine and racking up enormous repair costs.

When is the belt replaced?

Replacing the timing belt is part of regular auto maintenance and should operate between 70,000-110,000 miles. The cost of replacing the belt depends on the car you’re driving, but the average rate is a few hundred dollars. However, as we’ve already pointed out, the cost of breaking it can run in the thousands.

Signs the timing belt may fail The timing belt may fail without any signs, so if you’re in the mileage window, you should go ahead and fix it regardless. That said, your car often alerts you that the belt is wearing out.