A Comprehensive Guide to the 1999-2006 Mitsubishi Eclipse Alternator
Keep your 3G Eclipse powered up by understanding your alternator replacement options.
- For 2006 models, check for a broken B+ terminal post before replacing the whole alternator, as a cheap repair kit may be available per TSB-06-16-001.
- Denso is a trusted OEM-quality brand for the Eclipse; choosing a new or remanufactured Denso unit is a reliable option.
- Verify your engine (2.4L I4 or 3.0L V6) and original alternator amperage (85A, 90A, 100A, or 110A) before ordering to ensure compatibility.
- Always test the battery along with the alternator, as a bad battery can strain a new alternator and a bad alternator can ruin a good battery.
Is Your Eclipse Alternator Failing?
An alternator rarely fails without giving some warning signs. If you notice any of these symptoms with your 1999-2006 Eclipse, it's time to inspect your charging system. Ignoring them can lead to a dead battery, stalling, or damage to other electrical components.
🎬 Watch: A detailed breakdown of bad alternator symptoms and fixes.Common Symptoms of a Bad Alternator:
- Battery Warning Light: The most obvious sign is a battery-shaped light on your dashboard, indicating the system voltage is too low.
- Dimming or Flickering Lights: Headlights and dash lights that flicker, dim at idle, or get brighter when you rev the engine are a classic symptom. This happens because the alternator isn't providing a steady voltage.
- Whining or Grinding Noises: A high-pitched whine that changes with engine RPM or a grinding sound points to worn-out bearings inside the alternator.
- Slow or Malfunctioning Electronics: Power windows that move slowly, a radio that cuts out, or other electrical accessories acting strangely can be a sign of low voltage from a failing alternator.
- Frequently Dead Battery: If your battery keeps dying even after being jump-started or replaced, the alternator is the likely culprit because it's not recharging the battery as you drive.
- Stalling Engine: The fuel injection and ignition systems need electricity to run. If the alternator fails completely, the engine may stall while you're driving.
Check This Before You Buy a New Alternator! (TSB-06-16-001)
For 2006 Eclipse models (and related Mitsubishis), the company issued Technical Service Bulletin TSB-06-16-001. A loose nut on the main power connection (the B+ terminal) can cause it to overheat and break. This looks like a failed alternator, but it isn't. Mitsubishi offers a simple repair kit (Part No. MD632008) to fix just the terminal post. Always inspect this terminal for damage before spending money on a whole new alternator.
Choosing the Right Aftermarket Alternator
When shopping for a replacement, you'll find new and remanufactured options from various brands. For a Japanese vehicle like the Eclipse, the original equipment manufacturer (OEM) was often Denso.
- Premium Brands (Denso, Bosch): These brands are known for their OE-level quality and reliability. A new or remanufactured alternator from Denso is often considered the best choice for a direct, reliable replacement that matches factory performance. Bosch is another top-tier option known for durability.
- Quality Aftermarket Brands (Remy, ACDelco, WAI Global): These brands offer a good balance of quality and value. They are trusted in the industry and produce reliable new and remanufactured units that meet or exceed original specifications.
- Remanufactured vs. New: Don't be afraid of a remanufactured alternator from a reputable brand like Denso, Bosch, or Remy. These units have all wear components (like bearings and brushes) replaced with new parts and are tested to ensure performance. They can offer the same reliability as a new part for a lower cost.
Pro Tip: Check for Oil Leaks
A very common reason for repeated alternator failure on many vehicles is a leaking valve cover gasket. Oil drips down onto the alternator, seeps inside, and ruins the internal electronics. When you replace your alternator, look directly above it for any signs of oil leaks. Fixing a small oil leak can save you from buying another alternator in the future.
🎬 See how to replace a leaking valve cover gasket step-by-step.How Much Does a Mitsubishi Eclipse Alternator Cost?
The cost depends on the brand, whether it's new or remanufactured, and labor rates in your area. The replacement is a DIY-friendly job for those with some experience, but can also be done by any repair shop.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Alternator | $75 - $400 |
| Remanufactured Alternator | $60 - $250 |
| Used OEM Alternator | $40 - $85 |
| Shop Labor | $180 - $350 |
Frequently Asked Questions
Do I need to replace my battery at the same time?
Not always, but it's a good idea to test it. A failing alternator can damage a battery by either undercharging or overcharging it. Likewise, a bad battery that can't hold a charge puts extra strain on a new alternator. Most auto parts stores offer free battery and alternator testing. It's best to test both to be sure.
What amperage do I need for my Eclipse?
The 1999-2006 Eclipse used several different alternators with outputs ranging from 85 to 110 amps, depending on the engine (2.4L or 3.0L) and trim level. It is critical to match the amperage of your original alternator. If you have added significant electrical accessories like a powerful stereo system, you might consider a high-output alternator, which can range from 180 to 220 amps.
Can I install the alternator myself?
Yes, this is a feasible DIY project for someone with moderate mechanical skills. It requires basic metric tools (12mm and 14mm sockets/wrenches) and safely lifting the front of the vehicle. The process involves disconnecting the battery, releasing the belt tension, removing two main mounting bolts, and swapping the electrical connections. Expect it to take 1.5 to 2.5 hours.
🎬 Watch this DIY walkthrough for replacing the alternator yourself.What is a 'core charge?'
Many remanufactured alternators have a core charge. This is a refundable deposit you pay when you buy the part. You get the deposit back when you return your old, failed alternator to the seller. This allows the manufacturer to rebuild your old part for the next customer.
Helpful Videos
Technical Specifications
OEM Part Numbers: MD357737 MD354001 MD367307 MD373094 A002TA5394
Amperage: 85A, 90A, 100A, or 110A depending on engine and trim. Pulley: 6-Groove Pulley. Voltage: 12V.
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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:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your Eclipse Alternator Failing?
- Common Symptoms of a Bad Alternator:
- Check This Before You Buy a New Alternator! (TSB-06-16-001)
- Choosing the Right Aftermarket Alternator
- Pro Tip: Check for Oil Leaks
- How Much Does a Mitsubishi Eclipse Alternator Cost?
- Frequently Asked Questions
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