Have you ever heard a strange knocking sound coming from your engine and wondered what on earth was going on? Or perhaps you’ve noticed your vehicle vibrating more than usual, leaving you scratching your head? These could be signs that your crankshaft needs some attention, and ignoring them might cost you more than just peace of mind. 

Your crankshaft is essentially the backbone of your engine. It’s the component that transforms the up-and-down motion of your pistons into the rotational force that ultimately powers your wheels. Without a healthy crankshaft, your engine simply can’t function properly. It’s one of those critical parts that often gets overlooked until something goes wrong. 

In this guide, we’ll walk you through everything you need to know about crankshaft repairs. From understanding what causes damage in the first place to choosing the right repair specialist, we’ve got you covered. Whether you’re a seasoned mechanic or someone who just wants to understand their vehicle better, you’ll find practical tips and insights to help keep your engine running smoothly for years to come. 

Understanding Your Crankshaft: The Basics 

What Does a Crankshaft Actually Do? 

Think of your crankshaft as the heart of your engine’s mechanical system. It’s a long, heavy metal shaft that runs along the bottom of the engine block. As your pistons move up and down during combustion, the crankshaft converts this linear motion into rotational energy. 

This rotation is what eventually turns your wheels and gets you moving. The crankshaft connects to the flywheel at one end, which then links to your transmission. It’s a beautifully engineered piece of machinery that handles enormous forces every single second your engine runs. 

Common Signs Your Crankshaft Needs Attention 

Spotting problems early can save you a fortune in repairs. Keep an ear out for knocking or rumbling sounds coming from the engine bay. Excessive vibration, especially at idle, is another red flag you shouldn’t ignore. 

Other warning signs include oil leaks near the front or rear of the engine, difficulty starting, or your engine misfiring. If your check engine light comes on alongside any of these symptoms, it’s time to get things checked out properly. 

What Causes Crankshaft Damage? 

Wear and Tear Over Time 

Like any mechanical component, crankshafts don’t last forever. Years of constant rotation under extreme pressure naturally take their toll. The bearing surfaces gradually wear down, leading to increased clearances and reduced performance. 

High-mileage vehicles are particularly susceptible. Regular maintenance can slow this process, but eventually, wear becomes unavoidable. 

Oil Starvation and Lubrication Failures 

This is perhaps the most common culprit behind crankshaft damage. Your crankshaft bearings rely on a constant film of oil to function properly. When oil levels drop too low or the oil pump fails, metal contacts metal directly. 

The result? Rapid wear, overheating, and potentially catastrophic damage. Running your engine with dirty or degraded oil creates similar problems, as contaminants act like sandpaper on those precision surfaces. 

Overheating and Thermal Stress 

Engines generate enormous amounts of heat, and your crankshaft isn’t immune to its effects. When cooling systems fail or engines are pushed too hard, thermal expansion can cause warping and distortion. 

Repeated heating and cooling cycles also create stress fractures over time. These tiny cracks can grow until they cause serious structural failures. 

Manufacturing Defects and Material Fatigue 

Sometimes, problems stem from the factory itself. Casting flaws, improper heat treatment, or substandard materials can all lead to premature failure. Material fatigue is another concern, especially in high-performance applications where the crankshaft experiences greater stress than standard designs allow for. 

Can a Crankshaft Be Repaired or Does It Need Replacing? 

When Crankshaft Repair Is the Smart Choice 

Good news – many crankshaft problems can be fixed without needing a complete replacement. If the damage is limited to surface wear on the bearing journals, grinding and polishing can restore them to proper specifications. 

Repair makes sense when:

– Surface wear is within acceptable limits

– No cracks or structural damage exists

– The crankshaft can be reground to standard undersize dimensions

– Cost savings justify the repair over replacement 

When Full Replacement Becomes Necessary 

Sometimes, repair simply isn’t viable. Deep scoring, cracks, or significant warping typically mean you’ll need a new crankshaft. If the journals have already been reground to maximum undersize and still show problems, replacement becomes your only option. 

Severe collision damage or catastrophic bearing failure often leave crankshafts beyond saving. In these cases, investing in a quality replacement is the smarter long-term choice. 

Essential Tips for Effective Crankshaft Repairs 

Choosing the Right Repair Specialist 

Not all machine shops are created equal. Look for specialists with specific experience in crankshaft reconditioning. Ask about their equipment, processes, and quality control measures. 

Word of mouth matters in this industry. Chat with local mechanics and enthusiasts about which shops they trust. A seasoned specialist with proper credentials will always deliver better results than a general workshop trying their hand at precision machining. 

The Importance of Proper Crankshaft Grinding 

Crankshaft grinding requires incredible precision. The journals must be perfectly round and finished to exact specifications. Even tiny imperfections can lead to premature bearing failure.

 

Quality machine shops use specialised grinding equipment capable of achieving mirror-smooth finishes. They’ll also verify dimensions multiple times throughout the process. Don’t skimp here – proper grinding is the foundation of any successful repair. 

Balancing and Alignment: Getting It Right 

A crankshaft must be perfectly balanced to prevent vibration and uneven wear. During repairs, material removal can affect this balance. Professional shops will always check and correct balance after grinding. 

Alignment is equally crucial. The main bearing journals must all sit perfectly in line. Any deviation causes binding, excess wear, and reduced performance. Proper alignment verification should be standard practice for any reputable repair facility. 

Selecting Quality Replacement Bearings 

Your freshly repaired crankshaft deserves quality bearings. Using cheap, no-name bearings is a false economy that often leads to repeat problems. Stick with reputable brands specifically designed for your application. 

Make sure you order the correct undersize bearings to match your reground journals. Your machine shop should provide exact specifications. Double-check everything before installation – it’s much easier to verify now than to pull the engine apart again later. 

How Much Does Crankshaft Repair Cost in Australia? 

Factors That Influence Repair Pricing 

Crankshaft repair costs vary significantly depending on several factors. The extent of damage plays a major role – minor surface wear costs far less to fix than severely scored journals. 

Engine type matters too. Common four-cylinder crankshafts are cheaper to repair than complex V8 or diesel units. Labour rates differ between cities and regional areas as well. Expect to pay anywhere from $300 to $800 for grinding alone, with complete reconditioning packages running higher. 

Repair vs Replacement: Comparing the Costs 

In most cases, repair offers significant savings over replacement. A new crankshaft for a common engine might cost $500 to $1,500 or more, plus installation. Performance or rare applications can run several thousand dollars. 

When you factor in the full picture – including labour to remove and reinstall the engine – repair often makes excellent financial sense. However, if your crankshaft needs extensive work, the gap between repair and replacement narrows considerably. 

How Long Does a Crankshaft Repair Take? 

Timeframes depend on your mechanic’s workload and the complexity of your repair. The grinding process itself typically takes one to two days. Factor in inspection, cleaning, balancing, and any additional machining, and you’re looking at three to five business days for most jobs. 

If your crankshaft needs crack repair or straightening, add extra time. Engine removal and reinstallation at the workshop add further to the overall timeline. Plan for your vehicle being off the road for one to two weeks minimum during a complete crankshaft repair. 

DIY vs Professional Crankshaft Repairs: What You Should Know 

Let’s be direct – crankshaft machining isn’t a DIY job. The precision equipment required costs tens of thousands of dollars. Without proper training, you risk ruining an otherwise repairable crankshaft. 

However, competent home mechanics can handle removal and reinstallation themselves. This reduces labour costs significantly. Just make sure you’re comfortable working inside an engine before attempting it. Detailed workshop manuals and online tutorials can guide you through the process. 

How to Prevent Crankshaft Problems in the Future 

Regular Maintenance and Oil Changes 

Prevention beats repair every time. Regular oil changes with quality oil are your best defence against crankshaft wear. Follow your manufacturer’s recommendations – or change even more frequently if you drive in harsh conditions. 

Don’t forget oil filter changes either. A clogged filter restricts flow and starves your bearings of lubrication. Using the correct oil viscosity for your climate and engine is equally important. 

Monitoring Warning Signs Early 

Pay attention to your vehicle. Strange noises, vibrations, or warning lights deserve immediate investigation. Catching problems early often means simpler, cheaper repairs. 

Regular inspections help too. During routine servicing, ask your mechanic to check for oil leaks and unusual engine sounds. A proactive approach protects your investment and keeps you safely on the road. 

Keeping Your Engine Running Smoothly 

Your crankshaft works incredibly hard every time you turn the key. Understanding how it functions and what causes damage puts you in a much better position to keep it healthy. Regular maintenance, quality oil, and prompt attention to warning signs go a long way. 

When repairs become necessary, choosing the right specialist makes all the difference. Proper grinding, balancing, and quality bearings ensure your repaired crankshaft performs like new. While costs vary, repair often provides excellent value compared to full replacement. 

Take care of your crankshaft, and it’ll take care of you. Whether you’re driving across the outback or just commuting to work, a healthy engine means reliable, enjoyable motoring for years to come. If you’ve noticed any concerning symptoms, don’t delay – get things checked out and keep that engine purring smoothly.