Eclipse, Galant, Sebring & Stratus 2.4L Harmonic Balancer: Diagnosing Wobble, Vibrations, and Failure

Vehicle Fitment: A Critical Warning

Symptoms of a Failing Harmonic Balancer

A failing harmonic balancer can cause a range of symptoms, from minor annoyances to problems that can lead to catastrophic engine damage. Because it is made of rubber and metal, the most common failure is the rubber bond breaking down.

• Engine Vibration: The most common symptom is a new or unusual vibration felt throughout the car, especially when the engine is idling. In severe cases on the 4G64 engine, this vibration can be extreme enough to break other engine brackets and components.
• Visible Wobble: If you can safely observe the main pulley at the front of the engine while it's running, a failing balancer will often have a noticeable wobble. Do not continue to run the engine if the wobble is severe.
• Chirping or Squealing Noises: As the balancer fails, it can misalign the accessory drive belts, causing them to squeal or chirp. You might also hear a rattling or knocking sound as the metal rings begin to separate.
• Separated Pulley: In a total failure, the outer ring of the balancer can separate completely from the inner hub. If this happens while driving, it will cause an immediate loss of all belt-driven accessories, including the alternator (loss of battery charging), water pump (engine will overheat), and power steering.
• Timing Mark Issues: The outer ring of the balancer often has timing marks used for engine service. If the ring slips on the rubber, these marks will become inaccurate, making it impossible to set ignition timing correctly.

Buying a Used Engine Harmonic Balancer

For this specific part, a high-quality used OEM balancer can be a better choice than a cheap, new aftermarket part. The quality of the rubber compound and the bonding process are critical for longevity, and OEM parts are made to a higher standard than many budget replacements. Here’s what to inspect before buying a used unit:

1. Inspect the Rubber Ring: This is the most important check. Look for any signs of cracking, dry rot, or bulging in the rubber between the inner hub and outer ring. The rubber should be smooth and flush with the metal surfaces, not squeezed out or missing chunks.
2. Check for Oil Contamination: A common cause of failure is a leaking front crankshaft seal, which soaks the rubber in oil and causes it to break down. If the used balancer is coated in old oil, be extra critical of the rubber's condition.
3. Look for Separation: Try to twist the outer ring and inner hub by hand. There should be absolutely no movement between them. Check the front and back sides for any gaps forming between the rubber and metal.
4. Examine the Keyway: Look at the slot on the inside of the hub. It should have clean, sharp edges. If the keyway is damaged, rounded, or cracked, the part is junk and should not be used.
5. Check the Pulley Grooves: The grooves for the serpentine belt should be clean and free of major damage or corrosion that could shred the belt.

Replacement Information

Replacing the harmonic balancer on these 2.4L engines is a moderately difficult job that requires special tools. The main challenges are breaking loose the very tight center crankshaft bolt and safely pulling the balancer off the crankshaft without causing damage.

• Difficulty Rating: 4 out of 5
• Estimated Time: 2-3 hours
• DIY Feasible: Yes, for experienced mechanics with the right tools.

Required Tools & Procedures

A special puller is required to remove the balancer. For these Chrysler/Mitsubishi models, a three-jaw puller that hooks into the openings on the pulley is often used. An installer tool is also needed to press the new balancer back on. Do not use the crank bolt to draw the balancer on, as this can strip the threads in the crankshaft.

The crankshaft must be held stationary to remove and torque the center bolt. Mechanics often use a special chain wrench or a homemade tool that bolts to the pulley face and rests against the car's frame. Some may use the trick of resting a long breaker bar on the ground and bumping the starter, but this can be risky if not done correctly.

Simplified Replacement Steps:

1. Disconnect the battery.
2. Raise the front of the vehicle and remove the passenger-side front wheel and inner fender splash shield.
3. Loosen the tensioners and remove the accessory drive belts (power steering/alternator/AC).
4. Use a special tool or method to hold the crankshaft pulley stationary and break the center bolt loose. This bolt is extremely tight.
5. Use a three-jaw puller to slowly and evenly remove the harmonic balancer from the crankshaft.
🎬 See how to remove a Mitsubishi harmonic balancer
6. Apply a small amount of grease to the crankshaft snout and the new balancer's seal surface to prevent damage to the front main seal.
7. Use a harmonic balancer installer tool to press the new balancer onto the crankshaft until it is fully seated.
🎬 Watch: Proper removal and installation techniques for harmonic balancers
8. Install the center crankshaft bolt and torque it to specification. The torque spec for the 4G64 engine's crankshaft pulley bolt is 98 ft-lbs.
9. Reinstall the belts, splash shield, and wheel.

Cost of Replacement

The cost to replace the harmonic balancer can vary significantly based on the parts you choose and whether you do the work yourself.

Known Issues, Recalls, or TSBs

There are no official recalls or Technical Service Bulletins (TSBs) from Mitsubishi or Chrysler specifically for harmonic balancer failure on these vehicles. However, failure of the rubber element due to age, heat, and oil exposure is a well-documented wear-and-tear issue.

A safety recall (NHTSA Campaign ID: 15V338) was issued for the 2000-2005 Eclipse, 2001-2005 Sebring Coupe, and 2001-2005 Stratus Coupe, but it relates to the passenger-side sun visor and is not related to the engine.

Frequently Asked Questions (FAQ)