What is a 4G alternator?
There is no widely recognized device officially named a “4G alternator.” In practice, the term usually points to an alternator used on Mitsubishi’s 4G-series engines (such as the 4G63/4G64) or it may simply be a mislabel. This article explains what an alternator does, what “4G” might indicate in this context, and how to identify, install, and maintain the right unit for your vehicle.
What an alternator does
Understanding the basics helps explain why a correctly matched unit matters. An alternator is a belt‑driven generator that provides electrical power to a running vehicle and charges the battery. It converts mechanical energy from the engine into alternating current, which is rectified to direct current and regulated to a steady voltage by a voltage regulator.
- It charges the vehicle’s battery while the engine is running, ensuring others electrical systems have power even when the engine is idling.
- It powers electrical loads such as lights, infotainment, fuel pumps, and ignition systems, reducing reliance on stored battery power.
- It produces alternating current (AC) that is converted to direct current (DC) for the car’s electrical system.
- It uses a voltage regulator to maintain a consistent output, typically around 13.8 to 14.8 volts in a healthy system.
In short, the alternator keeps the battery charged and provides the continuous electrical supply a modern vehicle needs to operate.
What "4G" might mean in this context
The phrase “4G alternator” is not a standard technical term. In practice, it can refer to one of these possibilities, depending on who is speaking or which vehicle is involved.
- Compatibility with Mitsubishi’s 4G-series engines, especially the 4G63/4G64 family, where some owners and shops loosely refer to the replacement as a “4G alternator.” The actual part is an alternator designed to fit that engine family.
- A mislabel or shorthand used by aftermarket vendors, repair shops, or enthusiasts that doesn’t reflect an official catalog name.
- A reference to a particular generation or variant within a vehicle’s electrical system, sometimes conflated with 4G-era electronics or telematics terminology.
If you encounter this term, verify the exact engine code, vehicle year, and OEM or aftermarket part numbers. The safest approach is to match the replacement to the vehicle’s original part number, mounting provisions, connector type, and electrical rating.
Identifying the right 4G alternator and replacing it
To avoid misfit parts or charging problems, follow these steps to identify and install the correct unit for a 4G-family engine.
- Check the engine designation and year of your vehicle (for example, Mitsubishi 4G63 or 4G64). Look for the part number stamped on the alternator or consult the service manual or parts diagram for your model.
- Note the electrical specifications: system voltage (usually 12V in passenger cars) and the current rating (often listed in amperes, e.g., 60–100 A or more for newer vehicles).
- Examine the mounting points, belt alignment, and the electrical connector. The replacement should share the same bolt pattern, pulley type, and connector layout.
- Choose a unit from a reputable source—OEM, reputable remanufacturer, or a clearly compatible aftermarket option. Ensure the replacement has the same regulator type and pulley configuration.
- Install carefully: disconnect the battery, relieve belt tension, remove the belt, unbolt and detach the old unit, connect wiring, install the new unit, re-tension the belt, and reconnect the battery. After installation, start the engine and verify charging voltage (typically about 13.8–14.8 volts at idle and stable under higher RPMs).
Compatibility varies by model, so always rely on the official part numbers and manufacturer guidance rather than a name alone. When in doubt, consult a professional mechanic or the dealership’s service department.
Common issues and maintenance
Regular inspection can prevent charging problems and prevent breakdowns. Here are typical signs and maintenance tips to keep an alternator—whether labeled a “4G” unit or not—in good condition.
- Symptoms: Battery warning light, dim or flickering lights, a battery that repeatedly needs recharging, unusual noises (squealing belts or bearing wear), or voltage readings outside the normal range.
- Maintenance tips: Inspect and replace worn belts, check belt tension, clean corrosion from electrical connections, ensure good grounds, and replace worn brushes or regulators as needed. Most OEM or reputable remanufactured units last many years, but age, heat, and use affect longevity.
Addressing issues early can prevent unexpected vehicle failure and protect the charging system from damage.
Summary
The term “4G alternator” is not a standard designation in automotive electrical engineering. It generally points to an alternator used with Mitsubishi’s 4G-series engines or to a mislabel in parts listings. The core function remains the same: convert mechanical energy into electrical energy to charge the battery and power the vehicle’s electrical systems. To ensure compatibility, verify the exact engine model, part numbers, mounting provisions, and electrical specifications before purchasing or replacing an alternator. When in doubt, consult your vehicle’s manual or a qualified technician for guidance.
