BMW 735i Crankshaft Harmonic Balancer Replacement Costs

What is the Crankshaft Harmonic Balancer all about?

The harmonic balancer (also called “crank pulley damper”), connected to the crankshaft of an engine, reduces engine vibration and serves as a pulley for the drive belts. The balancer or “damper” is composed of two elements: a mass and an energy-dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber) element absorbs the vibrations. When the balancer fails, it is usually due to heat, salt, and or ozone deterioration of the rubber. General wear, tear, and stress on the rubber is also a factor.

Keep in mind:

Usually a problem with the harmonic balancer means that it needs to be replaced. However, sometimes the rubber insert that sits between the center and the outside of the pulley is all that is damaged. It is also possible for the bolt that holds the balancer in place to become loose, which can cause problems even if the pulley isn’t damaged.

How it's done:

Inspect the harmonic balancer.
Remove drive belts and balancer.
Inspect condition of crankshaft front seal.
Replace the harmonic balancer.
Reinstall drive belts.
Start car and check for proper operation.

Our recommendation:

Harmonic balancers aren’t a part of most standard inspections, so keep your eye out for warning signs. If you notice excess vibration or noise from the engine, then your balancer may be damaged, and you need to schedule an inspection.

What common symptoms indicate you may need to replace the Crankshaft Harmonic Balancer?

Vibration from engine.
Loud, abnormal engine noise, which increases with acceleration.

How important is this service?

The crankshaft harmonic balancer is connected to the crankshaft, and absorbs many of the vibrations that the engine creates. The engine creates a large amount of force that is delivered to the crankshaft, which transfers the power to the transmission. The harmonic balancer is responsible for absorbing some of the engine-created force so that the crankshaft doesn’t receive it all. When the harmonic balancer fails, the crankshaft receives all of the engine’s vibrations, and is susceptible to serious damage.

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