When Should I Change My Car's Timing Belt
In an internal combustion engine, you need to let air in to light the fuel. This happens when the valves are opened by the crankshafts and camshafts. In order to let in the correct amount of air, a timing belt connects the camshafts and crankshafts. As the belt rotates it keeps the two shafts moving in time. It also affects the other valves attached to the shafts, including the water pump. Since the late 1970's, high tensile fiber timing belts have replaced the metal chain kind. The latter may be making a comeback thanks to their increased durability. This oneHOWTO articles answers when should I change my car's timing belt? and will give you info on what needs doing when the answer is "now".
You can find three different types of timing drives:
- Gear timing drives: the need for replacing these gears is less frequent, but it doesn't mean they are a better system. They require having the camshafts and crankshafts close together. This is why a timing belt is often used. It allows for the two shafts to be in two places and connect them both. Gear timing drives also run the risk of "kick back" from the crankshaft which can cause increased wear and greater chance of damage.
- Chain timing drives: some vehicles use this metallic chain system because they usually last longer. Still, they should be changed after 350,000 km (220,000 miles). They also create more noise in the engine. If something snaps, they can cause more damage thanks to their heavier weight.
- Toothed timing belt: this is the most common system used today. It is economic and easier to use. However, it requires close supervision and maintenance to avoid it breaking. If you are thinking of buying a car you should always check the timing belt as replacing it can add considerable expense. You should also check it before going on a big trip. You don't want it snapping when you're too far from home to get back.
There isn't an exact period of time when you should change the timing belt. There are different considerations which may affect the timing belt, although weather is unlikely to be one of them. The main one is distance travelled. The approximate number of miles or kilometers your car has travelled will affect the condition of your timing belt. Generally, if your car has travelled anywhere between 60,000 miles (c. 100,000 kilometers) and 100,000 miles (c. 160,000 kilometers), you will at least need to check its condition. Each make and model varies. The best way to know how far your timing belt should get you is by checking the car's manual. They should provide an approximation of the distance it affords.
You may also notice problems with your timing belt when your car starts to lose power. The shafts need to be in time to allow the correct amount of air into the valves. If the valves open and close at the wrong time, it can cause the car to lose power. If your car starts to lose power, an old timing belt may be at fault.
The timing belt is made from entwined fiber with a synthetic rubber strap. The belt has teeth which lock into the corresponding teeth of the shaft powering gears. Some older timing belts have a less effective set of teeth or grooves in the belt, so they may wear out sooner. Another sign is if there is engine oil covering the belt. This can be detrimental to your timing belt's longevity.
When a timing belt is on its way out, there are tell tale signs. Even before you open the hood, you might hear noises which tell you it's time to change your timing belt. If you have a timing chain, the noise of it becoming loose will be obvious. That is if it hasn't already shut your engine down. It will cause loud rattling and you will be able to feel vibrations in the car. A fiber timing belt is more difficult to determine. As it is not made form metal, it will not strike the other engine parts with much noise. You still should be able to hear a low rumbling and even feel the vibrations change in the car. You akways need to be careful. While there may be some perceptible signs, it can break without obvious wanrning.
The best way to find out when you should change your timing belt is to look at it. Removing the timing belt cover is not easy, so you shouldn't attempt it if you are unsure of what you are doing. If you are having your car looked at by a mechanic they might need to remove the cover. They do this to have a look at the water pump or oil pump. While they are there, you can ask them to take a look at the timing belt as well. If it is worn smooth with cracks in the fiber material, it is likely on the way out. If it is a little smooth, but still in tact, you may have a while to go before there is a risk of snapping.
A conscientious mechanic will notice it while looking at the other parts and notify you. A charlatan will claim it needs replacing when it doesn't. Changing your car's timing belt can be expensive (anywhere up to $700). This is due to labor costs as the timing belt itself isn't very expensive. If you have a relatively new car with low mileage, needing to replace the timing belt is unlikely. If it is had a lot of miles on it, they are likely be correct. This is because a timing break snapping can be very costly.
When a timing belt breaks, it can be dangerous. The best thing that can happen is your car simply stops. The camshaft and crankshaft will no longer connect and the air won't enter the valves. This is why loss of power is something which should not be ignored. If the timing belt is even a little off, it could mean trouble as it might be about to break. If the timing belt breaks at high rotation, the force of it can break your shafts and bend the pistons. This damage is often irreparable and the car may be a write-off. This is particularly the case if it goes through the oil pump.
If you are getting your timing belt replaced, you should replace the water pump also. This is because the water pump itself is inexpensive, but the labor costs to get to it are not. This is the case in around 60% of all cars. You should ask your mechanic to take a look at your oil pump also and check the tensioners of the timing belt.
There are two types of 4 stroke engine - interference and non-interference. Interference means when the valves are open, they may enter the space where the pistons are working. Non-interference engines are the opposite. Keeping them from hitting each other is something controlled by the timing belt. If the timing belt breaks, it can cause the valves and the pistons to collide. This can be very dangerous, especially at high speeds.
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