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Crankshaft pulley: functions and failure symptoms
Have you noticed a decline in engine performance or that the engine-powered components aren’t working as they should be? The root cause could actually be a bad crankshaft pulley, causing havoc to the belt drive. Keep reading to learn how to spot common crankshaft pulley symptoms and find out more about replacements.
What does a crankshaft pulley do?
If you aren’t an automotive expert, you may not know what a car crankshaft pulley is or what exactly it’s for, nevermind what the symptoms of failure are. So, let’s start from there.
If you have a petrol or diesel car, your engine generates and transfers power with the help of a camshaft and crankshaft. The camshaft is the mechanism that controls the opening and closing of the engine intake and exhaust valves, which is timed precisely for optimal combustion.
The crankshaft is responsible for transferring the energy generated by combustion in order to power the car by converting the vertical movement of the engine pistons into a rotational movement. To paint a clearer picture of its significance, the engine RPM is a measurement of the rotational speed of the crankshaft.
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 138mm, Number of ribs: 5, for crankshaft
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 185mm, Number of ribs: 5, with bolts/screws, for crankshaft
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 185mm, Number of ribs: 5, for crankshaft
TOPRAN Crankshaft pulley
Decoupled
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 157mm, with bolts/screws
Crankshaft pulleys, aka harmonic balancers, are located on the end of the “crank” and are designed to distribute this rotational power through the pulley system to turn the car's drive belt. As the belt turns, power is transferred to the engine accessories, including the alternator, AC compressor, water pump, and power steering pump.
In addition to this, it acts as a balancer, balancing out the rotating crankshaft and dampening engine vibrations to ensure that everything operates smoothly.
What causes crankshaft pulley failure?
There are several possible causes of a failed crankshaft pulley, including the following:
- Improper installation
- Excessive belt tension
- Wear and tear
- Bearing failure
- Exposure to extremely high temperatures, coolant, or oil
It’s advisable to get a proper diagnosis as soon as you detect a problem with the pulley system. Replacing the components themselves can cost anywhere between £30 and £490 plus labour charges, depending on the vehicle make and model, as well as the year of manufacture. If the crankshaft itself is damaged, things start to get a bit more expensive with online crankshaft prices typically ranging between £95 and £1600.
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 180mm, Number of ribs: 5, with bolts/screws, for crankshaft, BMTS Turbo NEW
GATES Crankshaft pulley
Ø: 190mm, without accessories, PowerGrip™
CORTECO Crankshaft pulley
4PK+6PK, Ø: 192mm, Number of ribs: 3, 5, Decoupled, with mounting manual
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 180mm, Number of ribs: 5, for crankshaft
FEBI BILSTEIN Crankshaft pulley
6PK, Ø: 161mm, Number of ribs: 5, with bolts/screws, BMTS Turbo NEW
Bad crankshaft pulley symptoms
- Excessive engine vibrations – When the part fails, it may no longer be able to counteract vibrations coming from the rotating mechanism.
- Abnormal squealing sounds – You may hear abnormal crankshaft pulley noises as a result of a loss of tension or misalignment.
- Drive belt damage or misalignment – This can occur as a result of the excessive vibration and deformation or damage to the pulley, causing it to change the position of the belt.
- AC failure – The compressor is unlikely to function properly if the belt drive or pulley system goes down.
- A stiff steering wheel – If the drive belt gets damaged as a result of a bad pulley, the power steering pump may not be receiving enough power, making it more difficult to turn the wheels.
- An illuminated battery light – If the alternator is not being driven by the belt, it will not be able to maintain the car battery’s charge effectively. The battery will therefore lose its charge within a shorter period of time
If you’re hoping to save money by replacing the damaged parts yourself, you can find the best deals on aftermarket parts online. You can also compare parts and check whether they are compatible with your vehicle. Simply enter relevant details, such as the vehicle make and model and part name (e.g., “Crankshaft pulley BMW 1 Series”), or enter specific data, such as the VIN or OE part number.
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