Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. How Does a Timing Belt Work?

How Does a Timing Belt Work?

timing belt how it works

The timing belt is a belt made of rubber that keeps your camshaft and your crankshaft synchronized so that your valve timing is always right. Some vehicles have a timing chain instead of a belt, but it serves the same purpose. If your valve timing is off, your engine won’t run properly. In fact, it may not run at all. The belt also regulates the power steering and the water pump.

If you have timing belt problems, your mechanic can identify the trouble and will probably recommend that it be replaced.

How the timing belt works

In the four-stroke engine, there are four strokes, or phases. They are:

  • The intake stroke: The piston moves downward, and the intake valve opens to allow the mixture of air and fuel to enter the cylinder. At this stage, the exhaust valve remains closed.

  • The compression stroke: The piston moves up and compresses the fuel and air mixture. All valves are closed.

  • The combustion stroke: The piston moves down, allowing the spark plug to ignite the fuel and air mixture, delivering power to the vehicle. All valves are closed.

  • The exhaust stroke: The exhaust valve opens, allowing excess fuel and air to leave the engine. The intake valve is closed.

While all this is going on, the timing belt works to turn the camshaft pulley (some vehicles have two camshaft pulleys) in conjunction with the crankshaft pulley. A bad timing belt can cause the camshaft and crankshaft to be out of synchronization, and this can be catastrophic for the car’s engine. It throws the valve timing off, and you can end up with bent valves, bent piston rods, or completely destroyed pistons.

You may notice problems in time. Timing belt noise can be a red flag – it usually sounds like squeaking in the belt, or rattling if you have a timing chain. A timing belt problem should never be ignored, so watch for signs that there could be something wrong. The last thing you want is to have to rebuild your engine. As a general rule of thumb, you should plan on replacing the belt every 60,000 to 90,000 miles, or at least have it checked.

For this reason, your manufacturer will have recommendations as to how often your timing belt should be replaced. Generally, around the 80,000 mile mark it is prudent to get a mechanic to replace your timing belt to ensure that the engine continues to run efficiently.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...

Related questions

Q: Why Do Timing Belts Have Teeth and How Do They Work?

Timing belts have teeth for a frictional contact point to the sprockets, which have teeth to match with the belt. The sprockets are located on the engine crankshaft and camshaft. The timing belt is rotated by the engine's crankshaft which...

Q: 2006 Toyota Camry wont start after overheating due to missing radiator cap.

Sounds like the water pump went bad and broke the timing belt and now the engine will not start. Have the engine timing checked and the water pump to see if it is broken.

Q: Q: Belt squeaking

I believe for your vehicle there is only one drive belt. The serpentine belt is kept tight via the use of an automatic tensioner. If the belt is squeaking, the tensioner needs to be checked before the belt is replaced...