A Guide to the 1978-1985 Dodge Magnum Alternator
Keep your classic Mopar running strong by understanding its charging system and choosing the right new alternator.
- You must confirm if your Magnum requires an internally or externally regulated alternator before purchasing.
- Symptoms like dimming lights, a battery warning light, and a weak battery are the most common signs of failure.
- Consider upgrading to a higher-amperage alternator from a brand like Powermaster if you have added modern electronics.
- For this vehicle, a new aftermarket alternator is often a more reliable choice than a remanufactured unit.
Signs of a Failing Alternator
When your Magnum's alternator starts to fail, it will give you several warning signs. Ignoring them can leave you stranded with a dead battery. Look out for these common symptoms:
- Dimming or Flickering Lights: Headlights and dash lights that flicker, or dim and brighten as you rev the engine, are a classic sign of a weak alternator.
- Battery Warning Light: A "BATT," "ALT," or a battery-shaped icon on your dashboard indicates a problem in the charging system.
- Dead or Weak Battery: The alternator's job is to recharge the battery. If the alternator is failing, the battery will not get recharged, leading to a car that won't start.
- Whining or Squealing Noises: A grinding or whining noise can come from a bad bearing inside the alternator. A squealing sound could mean the drive belt is loose or worn, which also prevents the alternator from spinning correctly.
- Electrical Issues: A failing alternator can cause strange issues like a radio that stops working or power windows that are slow to operate.
Important: Internal vs. External Regulator
Mopar vehicles from this era used two types of voltage regulators. Some used an external regulator mounted on the firewall, while later models switched to an alternator with a built-in internal regulator. It is critical to identify which system your Magnum has before ordering a part. Using the wrong type will not work. Check for a box-like module on your firewall; if it's there and connected to the alternator wiring, you likely have an external regulator system.
Choosing the Right Aftermarket Alternator
For a classic vehicle like the 1978-1985 Dodge Magnum, new OEM parts are generally not available. Aftermarket parts are your main option, and many offer excellent quality and performance. Here's a look at the available brands:
Brand Quality & Performance
When choosing a replacement, consider your car's needs. Is it a stock restoration, or have you added electrical accessories like a modern stereo, electric fans, or extra lighting?
- Powermaster: Often considered a performance and upgrade brand. They offer high-amperage alternators that are great for vehicles with added electrical demands. While generally well-regarded, some users report fitment issues with stock brackets on certain Mopar engines and note that high-output units may require belt upgrades to prevent slipping.
- Remy: A long-established brand in the aftermarket. They offer reliable, new and remanufactured units that are a solid choice for a stock replacement, meeting or exceeding original specifications. Some owner reviews mention occasional premature failures, particularly with bearings.
- BBB Industries / MPA (Motorcar Parts of America): These brands often supply parts for major auto parts stores and offer a wide range of both new and remanufactured alternators. They are generally seen as a standard, value-oriented replacement option suitable for stock applications. Quality can be consistent, but it's always a good practice to have any alternator tested before installation.
Pro Tip: Consider an Amperage Upgrade
Stock alternators on these vehicles had outputs as low as 35-60 amps. If you've added any modern electronics, even just a new stereo, upgrading to a higher-output alternator (e.g., 95 amps or more) is a wise move. A higher-output unit provides more power at idle, which helps keep the battery charged and lights bright in stop-and-go traffic. Be aware that a significant amperage upgrade may require you to upgrade the main charging wire to handle the extra current safely.
Estimated Replacement Costs
The cost for a new aftermarket alternator for your Dodge Magnum typically falls within a reasonable range. The price varies based on the brand and amperage output.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Alternator | $85 - $153 |
| Shop Labor | $110 - $210 |
| Total Estimated Cost | $195 - $363 |
Frequently Asked Questions (FAQ)
Can I upgrade to a higher-amperage alternator?
Yes, and it's often recommended, especially if you have added electrical accessories like fans, a powerful stereo, or extra lights. Brands like Powermaster specialize in high-output units. Just ensure your wiring, particularly the main charge wire from the alternator, is heavy enough to handle the increased output to prevent a fire hazard.
How do I know if my alternator or battery is the problem?
A simple test can help. If you can jump-start the car, but it dies shortly after you remove the jumper cables, the alternator is likely the culprit. If the car won't start even with a jump, or the battery is old and won't hold a charge, the battery is the more probable cause. Most auto parts stores offer free battery and alternator testing.
Is a new alternator better than a remanufactured one?
For classic cars, a new unit is often preferred for peace of mind as it contains all new components. Remanufactured units can be a good value, but their quality depends on the rebuilder; they typically reuse the case and other hard parts, replacing only failed or worn components. Some owners have reported inconsistent reliability with remanufactured parts.
Are there any recalls on the 1978-1985 Dodge Magnum alternator?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database did not show any recalls specifically for the alternator on the 1978-1985 Dodge Magnum. Recalls for alternator failures have been issued for much newer Dodge models, but they do not apply to this generation.
Technical Specifications
Amperage: 35A to 100A+ (stock and upgrade options available). Voltage: 12V. Regulator Type: External or Internal (vehicle specific). Pulley: Single or Double V-Groove.
We Have This Part in Stock
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.