Signs of Timing Belt Problems

Timing belt breakage is one of the most common causes of cars breaking down. By having an idea of what a timing belt is and how long it typically lasts, you'll have a general idea of when you should replace it. Knowing common signs of wear will also help you from being stuck on the side of the freeway or other roadway with a broken timing belt.

Definition

A timing belt, timing chain or cam belt is part of an internal combustion engine. It connects the crankshaft to the camshaft(s), which control the opening and closing of the engine's valves. Some cars only have one camshaft; others have more than one. Timing belts are used with engines that have overhead camshafts in place of the old timing chains because they're easier and cheaper to manufacture.

Controlling the Engine's Valves

Camshafts open and close the intake and exhaust valves in the engine. This lets air in to create combustion and vents the exhaust that comes from the combustion explosions. A properly calibrated timing belt moves the camshaft(s) at half the speed of the crankshaft and in time with the motion of the pistons to keep the overhead cams turning at the right time and order so the engine runs properly.

Length of Use

A timing belt will last from 60,000 to 105,000 miles, depending on the make and model of the car, how it's driven and how well the vehicle is maintained. Other factors can contribute to how long the timing belt might last, including manufacturer defects. Check your owner's manual to get an idea of how long timing belts on your particular make and model last.

Preventive Care

If you perform regular maintenance on your vehicle, your mechanic will typically notice timing belt wear when you bring the car in for servicing. If the mechanic suggests you replace the timing belt, it's best to follow his advice. Doing so will save you a lot of trouble and money down the road.

Signs of Timing Belt Wear

Some common signs the timing belt could be wearing out include:
Your car is spewing out more exhaust than usual.
Your high-mileage car is hard to start.
The engine vibrates, causing your car to shake.
Your car shuts off while driving and spins over quicker than normal when you're trying to restart it.

When the Timing Belt Breaks or Fails

If the car bucks and stops running, it's probably too late. The belt is probably broken or has otherwise failed. The type of engine you have will determine how much collateral damage occurs when the timing belt breaks. In interference engines, a timing belt break could cause severe valve damage and damage to other engine parts. A noninterference, also known as "free-wheeling," engine typically doesn't suffer as much damage. But it will still cost you quite a bit to replace the timing belt once it's broken and other parts that were damaged when the belt broke.

Tip

While having the timing belt replaced, you should also consider replacing the water pump, belt tensioner, thermostat and camshaft seals. They'll probably already be worn or about to wear out. Replacing them at the same time as your timing belt can save you money on labor and save you extra trips to the mechanic.

Resources

• Gates Timing Belts
• Family Car Auto Parts--Timing Belts