Choosing the Right Alternator for Your 1968-1977 Mercury Montego
Keep your classic Montego's charging system healthy by understanding your alternator options.
- Most 1968-1977 Montegos use an external voltage regulator, which should be inspected or replaced with the alternator.
- Symptoms of failure include dim/flickering lights, a weak battery, and whining noises from the engine.
- Consider a higher-amperage alternator (e.g., 100 amps) if you have added modern electronics like a stereo or electric fans.
- Replacement is a straightforward DIY job for most owners, typically taking less than two hours.
Signs of a Failing Alternator in Your Montego
An alternator rarely fails without warning. For a 1968-1977 Montego, the electrical system is simpler than a modern car's, but the symptoms are similar. Watch for these signs:
- Dim or Flickering Lights: If your headlights or dash lights seem dim, flicker, or get brighter as you rev the engine, the alternator is likely struggling to provide consistent power.
- Weak or Dead Battery: The alternator is supposed to recharge the battery. If you find yourself with a dead battery, especially after replacing it recently, the alternator is the prime suspect.
- Strange Noises: A whining or grinding sound from under the hood that changes with engine speed can point to failing bearings inside the alternator.
- Warning Light: Your Montego may have a simple "ALT" or battery-shaped warning light on the dashboard. If this light comes on while driving, it's a direct signal of a charging system problem.
- Electrical Accessory Problems: If your radio, heater fan, or other accessories work intermittently or slowly, it can be a sign of low power from a failing alternator.
External Voltage Regulator: A Key Component
Many Fords and Mercurys from this era, including the Montego, used an external voltage regulator. This is a separate part from the alternator that controls the amount of electricity the alternator produces. If you are having charging problems, it's possible this separate regulator has failed, not the alternator itself. It's often recommended to test or replace the regulator when you replace the alternator.
Choosing a New Aftermarket Alternator
Finding a brand-new, Ford-stamped alternator for a classic Montego is nearly impossible. The market consists of new aftermarket parts and remanufactured units. For your 1968-1977 Montego, a new aftermarket alternator offers the benefit of all-new components and modern manufacturing, which can improve reliability over a remanufactured unit of unknown quality.
Aftermarket Brand Tiers for Your Montego
When shopping for a new alternator, you'll find several brands. Here’s a general breakdown of what to expect:
- Performance/Upgrade (Proform): Brands like Proform often specialize in higher-output alternators. These are a great choice if you've added modern electrical accessories like a powerful stereo, electric cooling fans, or brighter headlights. They often come in chrome or other finishes for a custom look. Some are "one-wire" alternators, which simplify wiring by using an internal voltage regulator.
- Standard Replacement (Remy, BBB Industries, MPA): These are well-known, major suppliers in the aftermarket. They produce new and remanufactured parts that are designed to meet or exceed original equipment (OE) specifications for fit and function. While generally reliable, quality can sometimes be inconsistent with any mass-produced part, as some user reviews indicate premature failures.
- Value Brands (USA Industries, Store Brands): These brands offer a cost-effective solution. They are typically new units designed to be a direct, functional replacement. While they meet basic requirements, they may not have the same long-term durability or performance consistency as more established brands.
Pro Tip: Check Your Amperage
Before you buy, know what you need. A stock Montego might have only needed a 45-60 amp alternator. If you have added any electrical accessories, upgrading to a 100-amp or higher alternator is a smart move to avoid future electrical issues.
Cost of a New Aftermarket Alternator (1968-1977 Mercury Montego)
| Part Type | Typical Price Range |
|---|---|
| New Aftermarket Alternator | $44.87 - $122.61 |
| Remanufactured Alternator | $50 - $150 |
| Performance Alternator | $100 - $250+ |
Frequently Asked Questions
Do I need to replace the voltage regulator at the same time?
For most 1968-1977 Montegos with an external regulator, it's a good idea. The regulator is a common failure point, and a bad regulator can damage a new alternator. If you upgrade to a modern "one-wire" alternator, the new unit will have an internal regulator, and you will bypass the old external one.
What is a "one-wire" alternator?
A one-wire alternator is a simplified design, popular in the hot rod and classic car community. It only requires a single wire connection from the alternator's output post directly to the battery. It has an internal voltage regulator and cleans up the engine bay by eliminating extra wiring. Proform is one brand that offers these.
Is it hard to replace the alternator on a Montego?
No, for a mechanically inclined person, it's a relatively simple job on these cars. It's usually mounted at the top of the engine and is easy to access. The process involves disconnecting the battery, loosening the belt, removing a few bolts and electrical connections, and then reversing the process.
How do I know if it's the battery or the alternator that's bad?
A simple test is to jump-start the car. If the car starts but dies as soon as you disconnect the jumper cables, the alternator is likely bad. If the car stays running, but won't start again later on its own, your battery is likely unable to hold a charge. Most auto parts stores can test both components for free to be sure.
Technical Specifications
Amperage ratings typically range from 45A to 65A for original units. Aftermarket options are available up to 100A or more. Most models in this year range use an external voltage regulator and a V-belt pulley.
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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.
- 🛍️ Shop This Part
- Signs of a Failing Alternator in Your Montego
- External Voltage Regulator: A Key Component
- Choosing a New Aftermarket Alternator
- Aftermarket Brand Tiers for Your Montego
- Pro Tip: Check Your Amperage
- Cost of a New Aftermarket Alternator (1968-1977 Mercury Montego)
- Frequently Asked Questions
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