Crankshafts are super crucial for car engines. They turn the back-forth motion of the pistons into a round-and-round motion that makes the wheels spin. But sometimes, crankshafts can break for many reasons – they get too worn out, don’t have enough oil, get too hot, are not aligned right, or get hit.
In this blog post, we will discuss why crankshafts break, how to identify if they need replacement, and how to repair them.
What Causes Crankshaft Damage?
Crankshaft damage can occur because of the following factors:
- Excessive wear: Over time, the crankshaft and its bearings can wear out due to friction, resulting in reduced performance, noise, and vibration. You can prevent this by using the correct oil grade, changing the oil regularly, and not overloading the engine.
- Improper lubrication: Lack of sufficient or poor quality oil can lead to insufficient lubrication of the crankshaft and its bearings, causing them to overheat and seize. Regularly checking the oil level and quality and adhering to the manufacturer’s recommended intervals and specifications can prevent this.
- Overheating: High temperatures can cause the crankshaft and its bearings to expand and deform, leading to cracks, warping, or bending. This problem may arise from insufficient cooling, low oil pressure, or faulty sensors. The problem can be prevented by maintaining the cooling system, ensuring adequate oil pressure, and replacing faulty sensors as soon as possible.
- Misalignment: The crankshaft and its bearings must be appropriately aligned to ensure smooth operation and prevent excessive stress. Misalignment can occur due to improper installation, faulty components, or engine damage. Fortunately, this can be corrected using appropriate tools and techniques, replacing defective components, and repairing engine damage.
- Impact: Worn ball bearings or crankshafts can also suffer damage from sudden or severe effects, such as hitting a curb, a pothole, or another vehicle. It’s important to drive carefully, avoid obstacles, and wear seat belts to prevent loss of power, noise, and vibration. The crankshaft breaking, bending, or twisting can cause these problems.
How to Realize that Crankshaft is Damaged?
Crankshaft damage can show up in different ways depending on the type and severity of the damage. Some common symptoms of crankshaft damage are:
- Loss of power: If the engine’s crankshaft is damaged, it may not be able to deliver the required energy and speed to the wheels, leading to decreased acceleration, performance, and fuel efficiency. A dynamometer can detect engine problems by measuring power output.
- Noise: If you hear strange sounds from your engine, it may be due to a damaged or misaligned crankshaft or bearings. You may hear noises like rattling, knocking, squeaking, or grinding. The sounds may vary in frequency and loudness depending on the engine load and speed. You can use a stethoscope to amplify the engine sounds and detect unusual noises.
- Vibration: If there’s something wrong with the part of the car that helps the engine work smoothly, called the crankshaft or its bearings, it can make the car shake a lot. In addition to making driving uncomfortable, it can also affect the car’s stability. You might feel the steering wheel, pedals, or seats shaking. If you want to be sure, you can use a vibration analyzer to see how much the car is shocking and how fast it’s happening.
- Oil leakage: If the engine’s crankshaft or bearings are damaged, it can result in oil leakage. In this case, oil pressure will be low, the engine will overheat, and the lubrication system will not function properly. You can see the oil leakage under the vehicle, engine, or dipstick. To detect oil leakage, you can use a pressure gauge that monitors the engine’s oil pressure.
Can the Crankshaft be Repaired?
The answer to this question depends on the type and extent of the crankshaft damage. Some kinds of crankshaft damage, such as minor wear, misalignment, or cracks, can be repaired by using various methods, such as:
- Grinding: When a crankshaft surface has slight wear, cracks, or warping, you can repair it by scratching the surface with a particular machine. This process removes a thin layer of metal and restores the original shape and size of the crankshaft.
- Polishing: Polishing the surface of a crankshaft is done using a particular machine to make it smoother and shinier. This process helps to reduce friction, allowing the engine to run better. If the crankshaft has any minor scratches, marks, or rust damage, polishing can help to repair it.
- Straightening: A hydraulic press is used to apply heat and pressure to the part to fix any minor bending or misalignment of the crankshaft. Doing so corrects its alignment and reduces any twisting that might have occurred.
- Welding: Sometimes, when a machine or vehicle works a lot, the metal inside can get damaged and crack or break. A particular machine called a welding machine is used to join the broken pieces back together. This way, the machine can keep working like it should without needing to be replaced. Welding can fix small cracks or breaks in the metal.
However, some types of crankshaft damage, such as severe wear, misalignment, cracks, or breaks, may not be repairable or may not be worth repairing due to the high cost, time, and risk involved. In such cases, the only option may be to replace the crankshaft with a new or refurbished one.
Costs of Crankshaft Repair:
- Crank grinding/polishing – $500-1000+
- Central/connecting rod bearings – $150+
- Straightening bent crank – $300-600
- Remanufactured crankshaft – $800-2000+
- Gasket set replacement – $150+
- Labor for disassembly/reassembly – 5-20 hours x shop rate
- Total typical costs – $1000-4000+
Suppose you suspect that the crankshaft of your vehicle is damaged. In that case, it is essential to understand that the specific repair solution and the associated costs will depend on the underlying cause and the severity of the damage.
A mechanic with professional training should conduct the diagnosis, as they can accurately assess the extent of the damage and recommend the most appropriate course of action. Attempting to diagnose or repair the damage without the necessary expertise can lead to further damage to the engine and result in additional, more expensive repairs. Therefore, seeking a professional diagnosis before undertaking any significant engine work is best.
Conclusion
Crankshaft damage can significantly affect your vehicle’s performance, safety, and durability. The crankshaft is a crucial part of the engine that converts the up and down movement of the pistons into rotational motion, which powers the wheels. Any harm to the crankshaft can lead to severe engine issues, including low power, poor fuel efficiency, and engine failure.
There are several reasons why crankshaft damage can occur, such as high mileage, poor maintenance, lack of lubrication, overheating, and manufacturing defects. If you notice any unusual noises, vibrations, or oil leaks coming from the engine, it could be a sign of crankshaft damage. In such cases, you should have your vehicle inspected by a qualified mechanic who can diagnose the issue properly.
Depending on the extent of the damage, the crankshaft may be repaired or replaced. Minor damage, such as scratches or nicks on the surface, can be rectified through grinding or polishing. However, a replacement may be necessary if the damage is severe, such as cracks, fractures, or bending. In any case, it is crucial to perform the repair or replacement by a certified mechanic with the expertise and equipment to handle the job correctly.
Following the manufacturer’s recommended maintenance schedule, including regular oil changes, filter replacements, and inspections, is essential to prevent crankshaft damage. It is also crucial to address any engine problems promptly and avoid driving your vehicle under extreme conditions, such as high speeds or heavy loads.
By taking proper care of your vehicle and staying alert to any signs of crankshaft damage, you can avoid costly repairs, ensure optimal engine performance, and extend the lifespan of your car.
People also asked about the crankshaft! [quick answers only]
When the crankshaft is damaged, people also ask the following questions,
What usually causes my crankshaft to fail?
Most crank failures originate from oil starvation, bearing failure, connecting rod failure, or severe overheating issues. Lack of maintenance is often a contributor.
How urgent is it to deal with my damaged crank?
It requires prompt attention as continued use can quickly worsen the damage. You risk complete breakdown or further engine damage by ignoring crank issues.
What are early signs of crankshaft problems?
Early signs include increased engine noise on startup or acceleration, vibration felt at higher RPMs, oil leaks from front/rear seals and gaskets, and oil-burning smells.
Can a bent crankshaft be repaired, or does it need replacement?
Special repair techniques can often straighten and save slightly bent cranks. But severely bent or twisted cranks typically require replacement.
Does crank repair require other engine parts to be replaced as well?
Connecting rods may be damaged, too, and bearings often need replacement. It’s wise to replace seals/gaskets while open and check pistons, cylinders, etc.
Is it expensive to fix a crankshaft?
Repairs can cost anywhere from $500 to over $2,000 or more in some cases. Simple fixes like grinding or polishing are usually less expensive. But it will be the most costly option if you need a total replacement along with machine shop work.
What can I do to prevent crankshaft damage?
Regular oil changes, not ignoring leaks/noises/vibration issues, avoiding overheating and over-revving. Quality parts and proper clearances in bearings are also important.
