Crankshaft
Ever wondered what’s really happening beneath the bonnet when your engine fires up? At the heart of it all is the crankshaft: a precision-engineered component that transforms the pistons’ vertical (up-and-down) motion into the rotational force that ultimately drives your vehicle forward.
The crankshaft is fundamental to engine function, and although it’s designed to be durable, it relies heavily on proper lubrication and timely servicing.
At South Coast Garage in Eastbourne, we’ve seen firsthand how neglecting regular maintenance can lead to serious crankshaft issues. In this blog, we’ll walk drivers in Eastbourne, Brighton, Lewes, and across East Sussex through what the crankshaft and crankshaft position sensor do, warning signs to look out for, and how to keep your engine protected through expert care.
So… What Is a Crankshaft, Anyway?
The crankshaft is a central component of any internal combustion engine. Found in the lower part of the engine block and housed within the crankcase, its job is to convert the linear (up-and-down) movement of the pistons into rotational energy. This rotational motion is what ultimately powers your vehicle’s wheels.
The crankshaft operates under extreme stress, handling immense forces generated by combustion. That’s why it’s engineered from high-strength materials and balanced with counterweights to reduce vibration and maintain smooth operation at varying speeds.
To protect it, your engine relies on a constant flow of clean, high-quality oil. The crankshaft contains internal oilways; narrow channels that allow lubricant to flow through and reach the critical surfaces between the crankshaft and its bearings. Without correct lubrication, metal-on-metal contact would occur, rapidly leading to heat build-up, wear, scoring, and eventually catastrophic engine failure.
At South Coast Garage, we know that preserving your crankshaft’s condition starts with using the right oil and following a consistent maintenance routine.
Understanding The Crankshaft’s Role
The crankshaft transforms the linear motion of the pistons into rotational energy. As your engine runs, each piston moves up and down in its cylinder. The crankshaft converts this movement into a smooth, continuous rotation, the motion needed to power your clutch, gearbox, and ultimately, your vehicle’s wheels.
But that’s not all. The crankshaft also drives several key systems within your engine. It maintains precise timing by rotating the camshaft through a timing belt, chain, or gear system. This ensures the valves open and close at exactly the right moment during the engine’s cycle. Additionally, the crankshaft helps run essential components such as the alternator, water pump, and air conditioning compressor via a system of pulleys and belts.
Put simply, a functioning crankshaft is essential for transmitting power in an engine, making it an absolutely critical engine part.
Potential Issues
The crankshaft is built to last the life of your engine, but only if it’s looked after. Skipping oil changes or using poor-quality oil can lead to a breakdown in lubrication. This can cause metal-to-metal contact between the crankshaft and its bearings, potentially resulting in scoring, heat damage, or even complete engine failure.
However, it’s not just the crankshaft itself that can cause problems. On modern engines, a more common failure point is the crankshaft position sensor. This small but vital component feeds real-time data about crankshaft position and speed to the Engine Control Unit (ECU). If the sensor fails, the ECU loses this critical input, meaning it can’t control ignition timing or fuel injection accurately. In some cases, the engine won’t run at all.
At South Coast Garage, we regularly diagnose issues involving both crankshafts and crankshaft sensors, helping drivers across Eastbourne, Brighton and East Sussex avoid bigger headaches by catching problems early.
Crankshaft Position Sensor
The crankshaft position sensor is a vital part of your engine’s electronic management system. Mounted to the engine block, it constantly monitors the position and rotational speed of the crankshaft. This data is sent to the ECU, which uses it to time ignition and fuel injection with pinpoint accuracy.
A faulty crankshaft sensor can cause a range of issues, from rough idling and poor acceleration to engine stalling or failure to start. That’s because, without accurate crankshaft position data, the ECU can’t manage the combustion cycle effectively. Faults with this sensor often trigger the engine management light and can be picked up during diagnostic scans.
If you’re experiencing intermittent starting problems or sudden stalling, South Coast Garage can carry out a full diagnostic check to pinpoint the issue and get you safely back on the road.
Indicators That Your Crankshaft or Position Sensor Requires Attention
If the crankshaft or position sensor begins to malfunction, it can lead to various engine problems. Be on the lookout for the following signs:
Starting Problems – The crankshaft sensor monitors the crankshaft’s position and speed when the engine is starting. If it fails to relay this information to the ECU, the engine may fail to start. While the engine may run without issues once started, the problem typically only becomes noticeable when attempting to restart the engine after it has been turned off, as the system relies on prior data to estimate the crankshaft’s position.
Poor Engine Performance – A malfunctioning sensor may cause the engine to misfire under certain conditions. Without accurate timing data, the ECU struggles to determine when to activate the spark plugs and fuel injectors. This can lead to rough idling, where the car shakes or vibrates when stationary, and decreased engine power, resulting in sluggish acceleration.
Check Engine Light – A faulty sensor often triggers your dashboard’s “Check Engine” light. This occurs when the ECU detects missing or inconsistent signals from the sensor.
Temperature-Related Failures – The crankshaft sensor is sensitive to heat, and high temperatures can cause it to malfunction intermittently. This can lead to the engine stalling, and your engine may only restart once the sensor has cooled down.
Unusual Vibrations or Noises – Excessive vibrations or odd sounds from the engine may indicate physical damage to the crankshaft, which requires prompt attention.
Recognising these warning signs early is crucial! Although identifying these symptoms can be challenging, detecting them early increases the likelihood of preventing more severe engine damage. It’s best to have a professional assessment of the issue to confirm whether the crankshaft or sensor needs attention before it leads to costly repairs.
How Can I Protect My Crankshaft?
Protecting your crankshaft and your engine as a whole starts with one simple habit: regular servicing. Sticking to the recommended service intervals ensures your engine oil is changed before it breaks down and loses its protective properties.
Using the correct oil grade is just as important. Engine oil isn’t one-size-fits-all; the wrong type can fail to provide adequate lubrication or maintain the right viscosity under pressure, leaving your crankshaft and bearings vulnerable to wear.
At South Coast Garage, we always refer to manufacturer specifications and use high-quality oil tailored to your vehicle’s requirements. During servicing, we also inspect for oil leaks, which can give early warnings of developing crankshaft issues.
Worried About Crankshaft Issues? We’re Here to Help.
At South Coast Garage in Eastbourne, we specialise in accurate diagnostics, professional servicing, and preventative maintenance to keep your engine running at its best. Whether you’re dealing with symptoms of crankshaft sensor failure or just want to stay on top of your regular servicing, our experienced technicians are here to help.
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We’re proud to support drivers across Eastbourne, Brighton, Lewes and the wider East Sussex area, with specialist knowledge, manufacturer-grade tools, and a commitment to doing the job right.
📍 Book your next service or diagnostic check with South Coast Garage today — call us on 01323 734473.
