Engine
Harmonic Balancer (Crank Pulley)
The harmonic balancer damps crankshaft vibration and drives the accessory belt.
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Combustion flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Absorbs torsional vibration from the crank
- Outer ring drives the accessory belt
- Often carries the crank position reluctor
When it fails
- Visible wobble of the pulley
- Rubbing or squealing (belt misaligned)
- Timing/crank sensor codes
- Vibration felt at idle
How to diagnose
- Watch the pulley run true while revving
- Check the rubber ring for cracks
- Compare timing marks against TDC
Maintenance
- Replace a delaminated balancer immediately — it can throw the belt
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.