How Does a Timing Belt Work?

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.


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Recent Timing Belt Replacement reviews

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Rating Summary
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Chris

22 years of experience
2223 reviews
Chris
22 years of experience
Toyota 4Runner V6-3.4L - Timing Belt - Anaheim, California
Chriss was really great. I appreciated his knowledge of my vehicle. He shared maintenance tips. Oh and he did a really good job with a difficult ask. New timing belt, drive belt, Radiator. Thank you!
Honda Odyssey - Timing Belt - Murrieta, California
We always use Chris for our auto repairs when he is available. He is very reliable and does a good job.

William

34 years of experience
517 reviews
William
34 years of experience
Ford Ranger L4-2.3L - Timing Belt - Phoenix, Arizona
I was scammed out of 2300 dollars by another mobile mechanic who said I needed a new engine. William came out and replaced the timing belt and water pump. He explained everything to me and was honest when asked certain questions. I will use this service again because William is now my mechanic. Great service.
Honda Pilot - Timing Belt - Phoenix, Arizona
Awesome person, friendly and did a great job. Had my timing belt done with the pulleys, water pump and thermostat. Defenitly knowledgeable in his field of work and will be using him again in my future repairs.

James

30 years of experience
873 reviews
James
30 years of experience
Honda Pilot V6-3.5L - Timing Belt - Kissimmee, Florida
This was a great first experience with YourMechanic. James was professional and worked diligently to get the job done. Highly recommend and will be using him again. Thanks!
Chrysler Sebring - Timing Belt - Orlando, Florida
James kept in touch with me the day of the repairs. Hard-working guy! Stay and finished job till late evening. Timing belt, new water pump and valve cover. So far so good! Thank you James!!

Jermaine

24 years of experience
244 reviews
Jermaine
24 years of experience
Lexus GX470 V8-4.7L - Timing Belt - Clarksville, Maryland
Jermaine always does a great job. He has worked on three of my cars, and done efficient and flawless work. He's a great guy too.
Honda Ridgeline - Timing Belt - Rockville, Maryland
I want to thank Jermaine for the quick, professional service on my 06 Honda Ridgeline. Outstanding. I didn't know what to expect, but after he completed the work and was explaining what he inspected afterward, I was very pleased. He was very professional and was able to help diagnose another potential issue. This is the first time I used "yourmechanic.com" and from the estimate I received (both timeframe and money), compared to the auto shops around town, I couldn't believe what could be done outside my home. After this experience, I will be a returning customer.

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