A failing Crankshaft can lead to serious engine damage if the warning signs are missed. test

Because the crankshaft sits at the heart of the engine, even small issues can quickly turn into expensive repairs if left too long.

If you’re dealing with unusual engine behaviour, these are some of the most common signs of crankshaft failure to watch for.

1. Knocking or Deep Engine Noise

One of the clearest symptoms of crankshaft failure is a heavy knocking or rumbling noise coming from the lower part of the engine.

This is often linked to:

• Worn crankshaft journals
• Damaged bearings
• Poor lubrication
• Excessive internal wear

If the engine starts making deep mechanical noise, it’s worth investigating early before more serious damage develops.

2. Low Oil Pressure

A crankshaft relies on proper lubrication to run smoothly.

If there is wear in the crankshaft or bearing area, oil pressure can drop, which is often one of the first signs that something inside the engine is no longer right.

Low oil pressure should never be ignored — especially if it appears alongside engine noise, vibration, or other internal engine symptoms.

3. Excessive Engine Vibration

A damaged or worn crankshaft can cause the engine to lose its balance.

This can lead to noticeable engine vibration, especially:

• At idle
• Under acceleration
• Through the cabin or steering wheel

If the engine no longer feels smooth, the crankshaft is one possible cause — particularly if vibration appears alongside unusual noise or poor running.

4. Metal Particles in the Oil

Metal contamination in the oil is always a warning sign.

If you notice metal shavings in the oil or debris in the oil filter, it may point to wear in the crankshaft, bearings, or other internal engine components.

This is one of the more serious signs of a damaged crankshaft and should always be checked properly before further damage spreads through the engine.

5. Sudden Loss of Performance

In more advanced cases, crankshaft damage can lead to:

• Poor engine performance
• Loss of power
• Difficult starting
• Rough running
• Or even full engine seizure

At this stage, the issue has usually gone beyond early wear and turned into a much bigger mechanical problem.

What Causes Crankshaft Failure?

Some of the most common causes of crankshaft failure include:

• Poor lubrication
• Low oil pressure
• Worn crankshaft bearings
• Oil contamination
• Overheating
• Incorrect tolerances during rebuild
• Poor-quality engine components

In many cases, crankshaft damage is not just about the crankshaft itself — it is usually part of a wider engine issue that needs to be diagnosed properly.

Why Early Diagnosis Matters

Crankshaft problems rarely stay small for long.

What starts as a bearing issue, lubrication problem, or internal imbalance can quickly develop into major engine damage if left unresolved.

Catching the warning signs early can help prevent:

• Bearing failure
• Crankshaft scoring
• Block damage
• Oil starvation
• And complete engine failure

That is why symptoms like knocking noise, low oil pressure, vibration, and metal in the oil should never be ignored.

Final Thoughts

Crankshaft issues are rarely isolated.

What starts as wear in a bearing, low oil pressure, or internal imbalance can quickly develop into wider engine damage if it is not addressed properly. That is why spotting the warning signs early matters — but just as importantly, so does using the right parts when the repair begins. At Apex Auto Parts UK, we stock an extensive range of crankshafts and supporting engine components, covering a wide range of engine codes, applications, and leading manufacturers.

From forged crankshafts and nitrided crankshafts to cast options and supporting rebuild parts, we can help supply what is actually needed for the job - whether that is a direct replacement, supporting components, or a more tailored rebuild setup, we have you covered. 

Shop our extensive range of crankshafts or call the team today.