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What is a crankshaft?

A crankshaft is an essential spare part that ensures the engine is running perfectly. This metallic part is composed of several pins or plates, called the main bearing journals which together make up a cylindrical bar which has an axis function, as it generates a rotational movement. Between the main bearing journals you'll also find the rod bearing journals or crankpins, which are other crankshaft cylinders establishing the rotational movement. The crankpins have mounted so-called con rods on them, which all connect to the pistons. Regardless of the engine type, there is only one crankshaft in the engine.

The purpose of the crankshaft is to convert the linear motion into a circular movement, which provokes a rotation. Thanks to this movement, the crankshaft will drive the moving parts such as the timing belt, the clutch or the crankshaft pulley (also called harmonic damper) which drives the serpentine (accessory) belt.

What are the symptoms of a damaged crankshaft?

If the crankshaft is failing and goes out of sync due to wear or a lack of lubrication, this will cause shocks between the bearings and the pistons, and this may seriously damage the engine of your car.

It is challenging to visually check if the crankshaft is damaged. That is why the crankshaft is equipped with a crankshaft position sensor connected to the engine computer.

What does a crankshaft sensor do?

The purpose of the crankshaft position sensor is to send information on the engine speed - meaning the number of rotations of the car engine per minute, on the speed of rotation of the crankshaft (RPMs), and on the position of the crankshaft respectively.

In case the crankshaft position sensor is failing, some symptoms will alert you: It can prevent your car from starting, the engine light can turn on, and you can notice an intermittent stalling. When this occurs, the crankshaft sensor should be replaced.

If the crankshaft of the engine is damaged, a warning light will appear in the dashboard of your car. If this happens, it is important that you drive your car to a garage as soon as possible to get it checked.

What is the crankshaft pulley?

The function of the crankshaft pulley is to drive the serpentine (accessory) belt, using the movement generated by the engine and the camshaft. This pulley consists of a steel or cast iron hub, and is made of rubber and steel fibers. It is located between the crankshaft and the serpentine (accessory) belt and absorbs the movements between those parts, which protects the engine.

In case the crankshaft pulley is damaged or worn, you might hear a hissing noise or feel vibrations. The pulley might also get blocked, which would lead to engine failure. In case of failure of the pulley, it will need to be changed. To do so, the mechanic will need to disconnect the battery and lift the car, after which he will have to unmount the right tyre and the mudguard. Then, the mechanic will remove the serpentine (accessory) belt. After this, it will then be possible to remove the crankshaft pulley by taking out the screws.