Things to Know About Engine Timing Belt - Toyota Service Information To Know in Salem, OR

Many people know that a broken timing belt is bad news for a car's engine, but you may not know much more than that. This simple component serves a valuable purpose, and can ruin your day if it fails. We find that knowing more about timing belts can give you a healthier respect for all that they do. Below, you'll find five things to know about the timing belt that your Toyota might have.

Timing belt

5. What a Timing Belt Does

To get a better idea of what a timing belt does, it's good to take a quick look at the combustion process of a gas engine. Intake valves in the cylinders of an engine open up to allow a mixture of fuel and air into the combustion chamber. The valve closes, and the piston moves up the cylinder to compress the mixture of fuel and air. A spark plug ignites the mixture, and the combustion pushes the piston back down again. An exhaust valve opens up, allowing the waste gases to be pushed from the cylinder as the piston returns to the top of its stroke.

The pistons are attached to a crankshaft, which turns the piston's movements into a rotational output. Camshafts are what open and close the intake and exhaust valves. The timing belt is there to make sure that the movement of the camshaft or camshafts is synchronized with the movement of the crankshaft.

Worn timing belt in engine

4. Why a Broken Timing Belt Is So Bad

Older vehicles used free-running or non-interference engines. In these engines, the pistons and the valves never occupy the same space in the cylinder. However, most modern engines are interference engines. These engines allow the pistons to create even more compression, producing more powerful and more efficient engines. The trade-off is that the valves and the pistons would occupy the same space in the cylinders if the valves were open and the pistons fully extended.

The synchronization of the crankshaft and camshafts means that this shouldn't happen--but a broken timing belt means that these two parts will no longer be synchronized. In a free-running engine, this would lead to reduced engine power and eventual stopping of the engine entirely. But things are different in interference engines. The pistons are likely to move up and strike the valves while they're still open, and that results in serious damage to a variety of internal engine parts. This is incredibly expensive to repair, and can sometimes cause enough damage that it might make sense to get a new engine--or a new car--rather than repair the damaged one.

3. The Symptoms of a Failing Timing Belt

Sadly, there usually aren't any symptoms that a timing belt is going to fail. There may occasionally be some small signs, like a ticking noise that might come from the engine. However, these symptoms are easy to miss, and hard to properly diagnose (since they can be caused by other problems, as well). Often, a timing belt will simply break with no warning. It's for this reason that it's vital to get your timing belt replaced when your owner's manual recommends. Doing otherwise is taking an awful risk.

Person replacing timing belt

2. Why Timing Belt Replacement Is Expensive

The timing belt itself is a simple rubber belt, and you'll find that the component itself isn't all that expensive. But call any place and ask for an estimate on replacing a timing belt and it will be hundreds of dollars. Why is this? Changing the timing belt on a vehicle is a long and labor-intensive process. To replace the timing belt, technicians have to dismantle a significant part of the engine, which takes time. They'll check seals, pulleys, tensioners, and more, before removing the old belt. Afterwards, they'll need to set the proper timing and test it to make sure the belt is working as it should. Finally, they will reassemble the engine. This takes hours of labor, and requires exceptional skill. Because of this, timing belt replacements tend to be some of the more expensive services your car will need. However, it's still cheaper than rebuilding an engine.

1. Not All Vehicles Have Timing Belts

If your owner's manual doesn't let you know when you need to have your timing belt changed, your Toyota may not have a timing belt at all. Instead, it might be equipped with a timing chain. As the name indicates, a timing chain serves the same purpose as a timing belt, but is a metal chain instead of a rubber belt. Unlike timing belts, timing chains likely won't need to be replaced. However, they're also heavier and louder than belts.

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  1. Capitol Toyota

    783 Auto Group Avenue
    Salem, OR 97301

    • Sales: (888) 459-7024

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Capitol Toyota

783 Auto Group Avenue Ne
Directions Salem, OR 97301

  • Sales: 503-399-1011
  • Service: 503-399-1011
  • Parts: 503-399-1011