Harmonic Balancer (Everything To know)

Although harmonic balancers are an essential component of any engine build, what exactly do they do? Is it necessary to have one? Is a bigger harmonic balancer better?

In this article, we discuss everything you need to know about the harmonic balancer, what it does, what happens when it fails, how you can go about replacing it and so much more.

What Is A Harmonic Balancer?

Harmonic balancers are additional drive components located at the front of the engine and connected to the crankshaft. Their main function is to reduce engine vibration and, in some cases, act as pulleys for drive belts.

Harmonic balancers are known by many names, such as crankshaft pulleys, dampers, and crankshaft balancers.

What Does A Harmonic Balancer Do?

Harmonic balancers are primarily designed to absorb vibrations from the crankshaft.

A four-stroke engine performs four strokes: intake, compression, power, and exhaust, and each piston in the engine performs a stroke as well during those four strokes. The crankshaft is turned by the movement of the pistons and their involvement in these four cyclic operations.

During the compression stroke of a four-stroke engine, other pistons move higher and push down on the vertical shaft of the crankshaft, which decreases the speed of rotation.

The crankshaft is subject to mechanical resonance through opposing forces, which could lead to a risky resonance phenomenon.

Harmonic balancers minimize high-frequency vibrations produced by the crankshaft. They are usually made up of a center hub, an insulator, and also an inertia ring.

In some designs, viscous fluid is also used. The crankshaft’s center hub is tightly bolted to the end. Turns and vibrations are absorbed by the rubber ring and inertia rings of the crankshaft.

The harmonic balancer creates a bolted-on or integral pulley that operates with the drive belt when an engine is running.

The pulley rotates due to engine power which turns the accessories driven by it such as the alternator, air conditioning compressor, and other engine-driven components.

bad Harmonic Balancer

Bad Hamonic Balancer Symptoms

The harmonic balancer, also known as a crankshaft damper or vibration damper, is an automotive component that is often overlooked. Although it is easy to forget about, it can cause severe engine damage if it fails.

If your harmonic balancer is bad, you may experience one or more of the following symptoms.

1. Vibrations in the engine

Harmonic balancers are designed for balancing the vibrations coming from the vehicle’s crankshaft. When the harmonic balancer becomes faulty, you might start feeling some strong vibrations coming from the vehicle’s engine compartment.

2. There Is a Noticeable Wobble in the Harmonic Balancer

Sometimes, the rubber insulators in the harmonic balancer begin to degrade, causing the Harmonic balancer to separate. This can cause noticeable wobbling when running the engine.

3. Unusual Noises

When an engine is running too fast, a faulty Harmonic balancer can cause a knocking, rattling, or squeaking sound that can be misinterpreted as an engine problem.

If the Harmonic balancer fails, the drive belt tensioner may begin moving abnormally. This can cause clicking or squealing noises when the car engine is running.

4. An Illuminated Check Engine Light

Crankshaft position and speed are determined by the crankshaft location (CKP) sensor signal, which is received by the primary computer in your vehicle, also called the powertrain control module (PCM).

The CKP sensor can recognize when it’s coming in contact with a toothed or notched wheel, usually found on the crankshaft and harmonic balancer, when the harmonic balancer isn’t there, though, the CKP sensor signals to the powertrain control module (PCM) that something is off and activates a check engine light.

5. Visible Wear and Damage

Another symptom of a bad harmonic balancer is Visible Wear and Damage. You might notice that the harmonic balancer has become worn out or damaged if you inspect it.

The rubber insulator might be worn out, which could cause the hub and outer part of the harmonic balancer to separate from each other.

Also Read: 700R4 Transmission – Everything You Need To Know

Harmonic Balancer Replacement Cost

A harmonic balancer replacement costs between $100-$550. However, in most cars, the average cost of replacing a harmonic balancer is approximately $200. Harmonic balancer replacement cost can vary depending on a few factors such as the vehicle type, brand, and the type of parts to be used in the replacement.

The cost of replacing a harmonic balancer depends on the type of vehicle and the brand of parts used during the job. The list below estimates the average costs for major brands that charge $100 an hour for labor.

  • Labor hours on a 2009 Toyota 4Runner equipped with a 4.7-liter engine is about 0.9 hours. Getting a replacement part from the factory will cost $261, while a Dayco part should be about $111. To replace the harmonic balancer in general, including the OE parts, it would cost approximately $251, and to use aftermarket parts, would cost about $201.
  • A 2014 Jeep Wrangler equipped with a 3.6-liter engine will take approximately 0.7 hours to replace the harmonic balancer. Using parts by Dayco will cost $46, and a factory replacement part will cost about $84. if you choose to use OE parts, it will cost about $154, and to finish the work using aftermarket parts, will cost approximately $116.
  • Labor time on a 2000 Ford Expedition with a 5.4-liter engine is roughly about 1.4 hours. ATP parts cost $45, while factory replacement parts cost $313. The use of OE parts will cost about $453, and to finish the work using aftermarket parts, would cost $185.
  • A 2004 Volkswagen Jetta equipped with a 2.0-liter engine needs about an hour of work to replace the harmonic balancer, which would cost $49 using aftermarket parts and $277 using factory replacement parts. You’d save some money by using aftermarket replacement parts for the job at $149 total instead of using factory replacement parts that cost about $377.

How To Replace A Harmonic Balancer

With the appropriate tools and knowing the right procedure, most DIYers can easily and quickly change a harmonic balancer. Replacement of a harmonic balancer requires three steps; many DIYers often face difficulties when attempting to remove the central crankshaft bolt. While others may experience difficulty getting the crankshaft pulley bolt back into place, both of these issues have simple solutions once you know what to do.

You need to have an appropriate size socket and an electric or battery-powered impact wrench. You can still get this work done without using the impact wrench, but it would be extremely difficult to complete the task.

The engine will rotate when you press down on the large break bar. Worse, a timing belt can be incorrectly fitted to an engine, causing it to turn backward, produce slack, or skip a tooth.

You can also complete this task by using an ANTI-crankshaft rotating tool. If a one-piece tool comes with the balancer, it simply screws into already installed bolt holes in the harmonic balancer. Typical harmonic balancers include a big offset socket that fits inside a hex slot.

The third option is to use a strap wrench to connect the harmonic balancer’s pulley section.

Follow the steps below to replace a balancer;

  1. To remove the harmonic balancer, disconnect the crankshaft center bolt.
  2. The crankshaft should be removed using the right harmonic balancer Puller. You should not attempt to use a jawed puller unless your harmonic balancer has threaded and factory-drilled holes. A puller like this will only remove the rubber isolation ring’s outer pulley rings. You need to use the right tool.
  3. Change the harmonic balancer unit Toss with a new one that meets the specifications.

NOTE: The old harmonic balancer can be reused once a new oil seal is fitted to the crankshaft. Be sure to inspect the harmonic balancer for any wear. If you notice any kind of wear, you have two choices: change the harmonic balancer or install a harmonic balancer repair sleeve.

Here is a video that shows you the harmonic balancer replacement process

Also Read: Ignition Coil Pack – Everything You Need to Know

Frequently Asked Questions About Harmonic Balancer

Can you drive with a bad harmonic balancer?

It is unwise to drive a car with a faulty harmonic balancer. The main bearings of the car will wear out quickly due to the spring-like action caused when the crankshaft rocks back and forth. This can lead to damage to the drive belts, causing them to snap, or even cause serious damage to other parts of the vehicle.

What is the cause of a harmonic balancer going bad?

Your vehicle’s crankshaft harmonic balancer can corrode from too much exposure to harsh chemicals or elements or even as a result of old age. Cracks in the crankshaft can arise, leading to the car’s ultimate failure.

How often should harmonic balancer be replaced?

It is possible for the harmonic balancers of some engines to last the duration of the life of the engine. Nevertheless, the harmonic balancers of some engines can only last 50,000 miles, and sometimes they don’t even last up to 10 years.

How can you test a harmonic balancer?

Inspect the harmonic balancer while running your car engine. You can check the harmonic balancer by shining a flashlight on it while it is moving. If you notice that the harmonic balancer is wobbling, it probably means it is bad.

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