Crankshaft Explained
Every time you start your car, the crankshaft quietly gets to work beneath the bonnet, converting engine force into rotational motion that keeps your wheels moving. You might not have heard of it, but your crankshaft is doing one of the most important jobs in your vehicle.
Fortunately, you don’t need to understand every last detail of your engine to care for it. With routine servicing and the right engine oil, you can keep your crankshaft in excellent health.
At Somerset Vehicle Services, we support drivers across Bridgwater, Taunton, and Weston-super-Mare with reliable maintenance that helps avoid expensive repairs. This guide explains what your crankshaft and crankshaft position sensor do, common warning signs to watch for, and why timely oil changes are a non-negotiable part of long-term engine care.
Crankshaft Basics: Location
The crankshaft is a heavy-duty component tucked inside your engine block. It’s mounted in the lower part of the engine, surrounded by protective housing called the crankcase, with the oil pan positioned below it.
This solid, precision-engineered shaft converts the vertical (up-and-down) movement of your engine’s pistons into the rotating force that drives your wheels. It’s equipped with counterweights to balance engine forces and includes internal oil passages (oilways) to keep the moving parts lubricated and cool.
Because it works under extreme stress and at high speeds, the crankshaft needs the correct lubrication at all times. Poor-quality oil or infrequent servicing can lead to friction, overheating, and in extreme cases, total engine failure.
What The Crankshaft Does
The crankshaft’s core purpose is to transform linear piston movement into rotary power. It doesn’t work alone! This rotation drives several other key parts of your engine:
- The camshaft (via a timing chain or belt) for synchronised valve timing
- Auxiliary systems like the alternator, air conditioning compressor, and water pump
- The clutch and gearbox, which pass the rotational energy to your wheels
What Might Go Wrong With Your Crankshaft
While the crankshaft is designed to last the lifetime of your engine, problems can arise, particularly if oil changes are skipped. This can leave you with a lack of lubrication or contaminated oil, which can lead to the early demise of this essential component.
More commonly, modern cars experience problems with the crankshaft position sensor rather than the crankshaft itself. If this electronic sensor fails, your engine may stall or refuse to start altogether.
Crankshaft Position Sensor: A Small Part With a Big Job
The crankshaft position sensor monitors the crankshaft’s location and rotational speed. It’s mounted to the engine block and sends data to your vehicle’s Engine Control Unit (ECU), which uses it to manage ignition timing and fuel injection.
If the ECU doesn’t receive this signal, it can’t fire the spark plugs or deliver fuel properly. That means combustion timing is compromised, and a vehicle that either won’t start or runs poorly.
This sensor can be sensitive to heat. Over time, wear and consistently high temperatures can cause it to malfunction, which is why early detection of faults is so important.
Red Flags: Your Crankshaft or Position Sensor Needs Attention
You don’t need to wait for your car to break down to know something’s wrong. Look out for these tell-tale symptoms of crankshaft or sensor trouble:
- Hard starting – If your engine struggles to fire up or fails to start altogether, the sensor may not be sending proper signals to the ECU. When the engine is already running, you may not even notice an issue here regardless of whether or not there’s an engine light, as the system estimates crankshaft position based on previous data. Problems only appear when you turn off the engine and try to restart it later.
- Engine misfires or poor performance – Irregular signals can disrupt ignition timing, leading to power loss, rough idling, or poor acceleration.
- Intermittent stalling – This can happen when the sensor is affected by high engine temperatures. The engine may stall and only restart after cooling.
- Warning lights – A faulty crankshaft sensor often triggers the ‘check engine’ light.
- Unusual engine noises – Clunking or heavy vibration could be a sign of deeper issues within the crankshaft assembly itself.
The moment you spot these symptoms, it’s time to book a professional technical evaluation. Early intervention is the best way to avoid expensive engine repairs.
Keeping Your Crankshaft in Optimal Shape
Here at Somerset Vehicle Services, we help extend the life of your crankshaft, and your entire engine, through simple but vital steps:
Regular Oil Changes
Following your manufacturer’s schedule for oil changes is one of the most effective ways to prevent wear. Fresh oil:
- Reduces friction between metal surfaces
- Cleans internal components of dirt and debris
- Cools critical engine areas
- Prevents rust and corrosion inside the crankshaft oilways
Choosing the Right Oil
We only use manufacturer-approved oils. These oils offer the best protection for your engine’s internal components, especially the crankshaft and its bearings. Incorrect oil grade or low-quality oil may lead to insufficient lubrication, shortening the life of your engine.
Professional Maintenance
Routine inspections allow us to spot issues early, replace filters, check oil levels and quality, and make sure all engine sensors are functioning correctly. We use the latest diagnostics to assess sensor health and pinpoint crankshaft-related faults before they turn into major repairs.
Choose Us for Reliable Car Care
With so much riding on a properly functioning crankshaft and sensor, timely, professional care is essential. At Somerset Vehicle Services, we take pride in delivering expert vehicle servicing to drivers in Bridgwater, Taunton, and Weston-super-Mare, reflected in our {{average-rating}} star Google rating from {{review-count}} satisfied customers.
Here’s what you can expect:
- 12-month guarantee on all parts and labour
- Experienced technicians using specialist tools
- Genuine or Premium OEM-grade parts and fluids every time
- Transparent pricing and friendly, honest advice
We’re here to help keep your engine reliable, your journeys smooth, and your vehicle in top shape for the long haul.
Got a concern about your crankshaft or sensor? Give us a call on 01458 210402 to speak to one of our expert technicians or to schedule a service today.
