Alternator A3TG1391 12V 90A 4PK Mazda 3 5
Applicable models:MAZDA A3 2.0L 2.3 5 2.3L
Reference part number:A3TG1391A LF50-18-300 A3TG1391, A3TG1391A, A3TG1391AD, A3TG4791 A003TG1391A, A003TG1391AD, A003TG4791, JA1902,KELLA8EL738211711,KRAUFALM1902 ALM1902BA,ALM1902BS,ALM1902GB,ALM1902US ALM1902UX,ALM1902YX,ALM1902ZD LF5018300R0A,LF5018400,MitsubishiA003TG1391 LF1F18300,LF1F18300R00,LF5018300,LF5018300A, 11008N,, ALT3528 115786 12060833
| Rated output : | 12V 90A |
| Pulley : | 4PK |
| Size : | 24*18*17single unit inner box |
| Weight : | net weight：6.3KG gross weight：6.7KG |
| Packaging : | Neutral kraft paper packaging |
| Spot/Pre sale : | Spot goods |
| Warranty : | 1 year |
| Product number : |
| Type : | ACgenerator Alternator |
| Specification : | 12V 90 A |
| Pulley : | 4PK |
| Brand : | nuojin |
| Number : | LF2L18300 |
| Quality : | new |
| Delivery time : | 10 day |
Product Overview
The A3TG1391 is a Mazda OE-spec replacement alternator delivering 12V 90A output with a 4-rib (4PK) pulley, engineered for Mazda 3 and Mazda 5 models with the 2.0L and 2.3L MZR engine family. This brand-new aftermarket unit, identified by the LF50-18-300 and A003TG1391 cross numbers, matches the original charging-system specification of these Japanese platforms.
Fitted with internal regulator design, this alternator is stocked in-house with a 1-year warranty and 10-day dispatch lead-time. The 90-amp rating is factory-correct for the electrical load of these vehicles, supporting climate control, powered accessories, infotainment and battery management.
Key physical specs: net weight 6.3 kg, gross weight 6.7 kg, overall dimensions 240 x 180 x 170 mm, supplied inside neutral kraft inner carton.
The Mazda MZR 2.0L / 2.3L Platform and 90A Charging System
Mazda 3 and Mazda 5 models with the 2.0L and 2.3L MZR engine family carry a substantial factory electrical load from climate control, powered accessories, infotainment and lighting, which is why the charging system is rated at 90A.
This unit is specified as 12V 90A, matching the factory charging-system specification of these platforms. The 4PK pulley matches the original accessory-belt layout. Installing a pulley with the wrong rib count will cause belt mis-tracking, slippage, premature belt wear and charging faults. Never substitute a 1PK, 2PK, 6PK or 7PK unit for this 4PK drive layout. Always cross-check against your old alternator before ordering.
Technical Specifications
| Parameter | Specification |
|---|---|
| A3 series (Denso) numbers | A3TG1391, A3TG1391A, A3TG1391AD, A3TG4791, A003TG1391, A003TG1391A, A003TG1391AD, A003TG4791 |
| Mazda LF series numbers | LF50-18-300, LF5018300, LF5018300A, LF5018300R0A, LF5018400, LF1F18300, LF1F18300R00, LF2L18300 |
| ALM / supplier numbers | ALM1902, ALM1902BA, ALM1902BS, ALM1902GB, ALM1902US, ALM1902UX, ALM1902YX, ALM1902ZD |
| Reference/OEM cross | 8EL738211711, JA1902, 11008N, 12060833, ALT3528, 115786 |
| Voltage | 12V |
| Amperage | 90A |
| Pulley | 4-rib fixed pulley (4PK) |
| Regulator | Internal |
| Engine | Mazda MZR 2.0L / 2.3L (verify engine code) |
| Quality | NEW |
| Warranty | 1 year |
| Net Weight | 6.3kg |
| Gross Weight | 6.7kg |
| Dimensions | 240 x 180 x 170mm |
| Packaging | Neutral kraft box |
| Lead Time | 10 days, in stock |
Engine Compatibility and Cross Reference
This alternator fits the following vehicles. Do not rely solely on the model name for fitment validation; always verify engine code, production year, old-part OE number, pulley rib-count and amp label on your original alternator.
| Vehicle | Engine | Notes |
|---|---|---|
| Mazda 3 | 2.0L / 2.3L MZR (verify engine code) | Verify 4PK, 90A and mounting layout |
| Mazda 5 | 2.0L / 2.3L MZR (verify engine code) | Verify 4PK, 90A and mounting layout |
Multiple Mazda, Denso and supplier OE numbers appear across production batches and regional market specifications for this same alternator family. If your original unit bears one of the listed cross-reference numbers, A3TG1391 serves as a direct drop-in replacement.
What to Look for in a Replacement
Follow these five verification steps before placing your order to avoid wrong-part returns:
1. Check the amperage label on your old alternator: confirm it is rated for 90A. Different amp ratings are not interchangeable.
2. Count pulley ribs: this unit requires 4PK (4-rib). Units with a different rib count are incompatible for this accessory drive setup.
3. Confirm the exact Mazda model, engine code and production year of your vehicle.
4. Match against OE / reference part numbers stamped on your original housing.
5. Weight cross-check: genuine matching unit weighs approximately 6.3 kg net; significant weight difference indicates wrong assembly.
Application Scenarios
Independent repair shops and Mazda specialists servicing Mazda 3 and Mazda 5 models across Asia-Pacific, Europe, North America, the Middle East and Latin-America.
Parts counters and jobbers stocking Japanese compact charging-system components.
Vehicle owners restoring and maintaining original-spec Mazda models.
Used-car export traders supplying pre-owned Mazda vehicles to global secondary markets.
Owners with moderate accessory loads who require a factory-spec charging system.
FAQ
Q: Which Mazda models does this alternator fit?
A: It fits Mazda 3 and Mazda 5 models with the 2.0L and 2.3L MZR engine family. Always verify against the OE number, pulley and mounting layout of your original alternator before ordering.
Q: My old alternator shows OE number LF50-18-300 or A003TG1391, will A3TG1391 work?
A: Yes. These numbers belong to the same alternator family, differing only by production revision and market specification. It serves as a direct replacement.
Q: Is this alternator 4PK?
A: Yes. This unit uses a 4-rib (4PK) pulley. Confirm the rib count on your old alternator before ordering.
Q: Is this a Denso-pattern alternator?
A: Yes. The A3TG1391 and related A3T-series cross numbers identify this as a Denso-pattern unit matching the Mazda OE specification.
Q: What is your warranty and lead-time?
A: Goods are in stock with a 10-day dispatch lead-time. A 1-year warranty applies from installation date; warranty excludes damage caused by mis-installation, wrong belt tension, or vehicle-wiring faults.
In Practice
For technicians working on Mazda MZR vehicles: Before removing the existing alternator, perform charging-system diagnostics. Measure battery terminal running voltage with a multimeter. Weak batteries, corroded ground connections or a faulty main harness can mimic alternator failure symptoms. Always disconnect the battery negative terminal before commencing removal work.
Take photos of wiring connectors and bolt positions during disassembly to avoid mis-routing during reassembly. Observe correct belt tension: 10-15 mm deflection when pressing the belt mid-span. Over-tightened belts accelerate alternator bearing wear; loose tension creates slipping and insufficient charging. Torque mounting bolts to Mazda workshop-manual specifications.
Inexperienced home mechanics are recommended to entrust replacement work to a qualified auto-electric repair shop. Incorrect wiring risks burning the alternator or vehicle-system components.
References
Vehicle applications are compiled from the original equipment fitment data for the A3TG1391 alternator family covering the Mazda 3 and Mazda 5 models listed in the Engine Compatibility table, verified against actual installation tests and after-sales maintenance experience.
