A Guide to the Accessory Drive Belt Idler Pulley for the 2006-2012 Mitsubishi Eclipse
Hearing a squeal or chirp from your engine? Your Eclipse's idler pulley might be the cause.
- A squealing or grinding noise from the engine is the primary symptom of a failing idler pulley.
- Due to factory recalls on the belt system, it's critical to inspect all pulleys and the tensioner for wear.
- For best results, replace the serpentine belt and inspect the tensioner when you replace the idler pulley.
- High-quality aftermarket brands like Gates, INA, or Continental are excellent choices for this repair.
Signs of a Failing Idler Pulley
A bad idler pulley gives clear warning signs before it fails completely. The most common symptom is noise coming from the engine bay. You might hear:
- Squealing or Whining: A high-pitched squeal, especially on a cold start or when you accelerate, often points to a worn-out bearing inside the pulley.
- Chirping or Chattering: A rapid chirping sound can mean the pulley is loose or the bearing is failing.
- Grinding or Rumbling: A rough, low-pitched noise indicates the bearing is badly damaged and close to seizing.
Besides noise, you should also look for physical signs of failure:
- Wobbling Pulley: With the engine running, look at the pulley. If it appears to wobble, the bearing is worn out.
- Visible Wear: Check for rust, scoring, or damage on the pulley's surface.
- Belt Damage: A bad pulley can damage the edges of the serpentine belt, causing fraying.
Known Issues: Recalls for the Belt Drive System
The 2006-2012 Eclipse generation was subject to important recalls involving the accessory drive system. Even if your car wasn't serviced, these issues highlight weak points to be aware of.
NHTSA Recall 14V-562: This recall addressed the original factory drive belts, which could cause the plastic pulleys to wear down unevenly. This wear could lead to the belt coming off, causing a loss of power steering and battery charging. The fix was a new, improved rubber belt and pulley replacement if wear was found.
NHTSA Recall 18V-069: This recall was for the automatic belt tensioner on some 2008-2012 models. The tensioner flange could crack, causing the belt to detach suddenly. This is a separate part from the idler pulley, but it's in the same system and should be inspected during any belt service.
Choosing the Right Aftermarket Idler Pulley
For a part like an idler pulley, a high-quality aftermarket brand often provides the same performance as the original OEM part for less money. The key is choosing a brand known for quality bearings. Here’s a breakdown of available brands.
Premium Brands
These brands are often original equipment manufacturers for many car companies and are known for their quality and durability. They are an excellent choice for long-term reliability.
- Gates: Widely regarded as a top choice for all belt drive components, including pulleys and tensioners.
- INA: A major OEM supplier for European cars, known for high-quality bearings. Many other brands may rebox INA components.
- Continental: Another top-tier OEM supplier known for excellent rubber belts and reliable pulleys.
Standard & Value Brands
These brands offer a good balance of quality and price, making them a solid choice for most repairs.
- Dayco: A well-known aftermarket brand that produces reliable pulleys and belts. Some users note their plastic pulleys may not feel as robust as premium brands, but they are a dependable option.
- Dorman: Offers a wide range of replacement parts and is a common choice for general repairs.
- Four Seasons / Hayden: These brands are established in the aftermarket and provide functional, budget-friendly replacement parts.
Pro Tip: Replace More Than Just the Pulley
Since you already have to remove the serpentine belt to change the idler pulley, it is highly recommended to replace the belt and the automatic tensioner at the same time. These parts wear together, and replacing them all at once saves you from doing the same job twice.
Aftermarket Idler Pulley Cost for 2006-2012 Mitsubishi Eclipse
| Part / Service | Estimated Cost |
|---|---|
| New Aftermarket Idler Pulley | $28 - $87 |
| New OEM Idler Pulley | $95 - $145 |
| Shop Labor | $85 - $125 |
| Total Professional Replacement (Aftermarket Part) | $113 - $212 |
Cost estimates are approximate and can vary by location and chosen parts.
Frequently Asked Questions (FAQ)
Is the idler pulley the same as the tensioner pulley?
No. The idler pulley is a fixed, free-spinning pulley that only guides the belt. The tensioner pulley is mounted to a spring-loaded arm that applies pressure to the belt to keep it tight. On the 4G Eclipse, the tensioner is what you will move with a wrench to get the belt off.
Can I replace just the bearing in the pulley?
While it is sometimes possible to press out the old bearing and install a new one, it requires special tools. For most people, it is faster, easier, and more reliable to replace the entire pulley assembly.
How difficult is it to replace the idler pulley myself?
This is a DIY-friendly job for someone with basic mechanic's tools. Access is gained through the passenger-side wheel well. You will need a breaker bar or serpentine belt tool to release the belt tension, and a socket set to unbolt the pulley. The entire job typically takes about an hour.
Does my V6 have more than one idler pulley?
Yes, the 3.8L V6 engine has a more complex belt system. It includes a main serpentine belt with its own idler and tensioner, as well as a separate belt and tensioner pulley for the power steering system. Be sure to identify which pulley is making noise before ordering parts.
Technical Specifications
OEM Part Numbers: MD374878
Both the 2.4L 4-Cylinder and 3.8L V6 engines use a single main serpentine belt with an automatic, spring-loaded tensioner. The 3.8L V6 has an additional, separate belt and idler for the power steering system.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mitsubishi Eclipse:
- 🛍️ Shop This Part
- Signs of a Failing Idler Pulley
- Known Issues: Recalls for the Belt Drive System
- Choosing the Right Aftermarket Idler Pulley
- Premium Brands
- Standard & Value Brands
- Pro Tip: Replace More Than Just the Pulley
- Aftermarket Idler Pulley Cost for 2006-2012 Mitsubishi Eclipse
- Frequently Asked Questions (FAQ)
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