Engine
Crankshaft
The crankshaft turns the pistons’ up-down motion into rotational power.
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Combustion flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Converts reciprocating to rotary motion
- Drives the flywheel and accessories
- Holds main and big-end bearings
When it fails
- Knocking or rumbling from the bottom end
- Low oil pressure warning
- Metal particles in the oil
- Engine vibration
How to diagnose
- Check oil level and pressure
- Listen for a deep knock under load
- Oil analysis for metal debris
Maintenance
- Change oil on schedule — the crank lives on oil
- Fix oil leaks that drain the sump
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
Piston & Rings
Pistons convert combustion pressure into linear motion that the crankshaft turns into rotation.