Bosch AL0921N Alternator
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Bosch
 Alternator (New)

Bosch AL0921N Alternator

Brand Bosch AL0921N
Voltage 12
Fan Type Internal
Ground Type Negative
Mounting Configuration Code Short
Rotation Direction Clockwise (right)
One Wire Capable No
Pulley Included Yes
External Regulator Included Yes
Pulley Groove Quantity 6
Outside Pulley Diameter 56
Regulator Type Internal
Decoupled Or Clutch Pulley Yes
AC Service Tap No
Amperage Rating 140
Mounting Type Foot-mounted
Brushless No
Automotive Item Weight (lbs) 14.263908 lb
New Or Remanufactured New
Product Length 7.322835 in
Pulley Type / Belt Type (Alternator) 6s
Product line Alternator (New)
Fits Audi and Volkswagen · 30 vehicles

New alternator. Bosch Premium alternators are built and tested for dependable performance and reliability.

Internal regulation. Includes an internal regulator for a cleaner, more integrated charging setup.

Pulley included. Comes with a pulley and decoupled clutch design for smoother belt operation.

Cross-references 06J903023A, 06J903023G and 06K903024A for the same application. See all 4.

$433.89Free shipping
In stock · usually ships same day before 1pm CST
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Order total $433.89
Free shipping to the continental U.S.
Free returns within 60 days if it doesn't fit when fitment is verified.
Not what you need? See all Alternator options

Bosch AL0921N Alternator Overview

The Bosch AL0921N is a new 12-volt alternator built for consistent charging performance and dependable electrical output. It is a fitment-based replacement for select Audi and Volkswagen applications, including Audi A3, A3 Quattro, S3, TT Quattro, TTS Quattro, and Volkswagen Golf, GTI, Golf Alltrack, Golf SportWagen, Golf R, Atlas, and Atlas Cross Sport.

Bosch Premium Alternators are engineered and tested for reliable operation in demanding daily driving conditions. The AL0921N uses an internal regulator, internal fan, and clockwise rotation, with a 140-amp amperage rating, pulley included, and a decoupled clutch pulley for proper belt system operation.

Key Features

  • 12-volt new alternator with 140-amp output
  • Internal regulator and internal fan design
  • Clockwise rotation with negative ground
  • Foot-mounted, short mounting configuration
  • 6-groove pulley included, 56 mm outside pulley diameter
  • Decoupled or clutch pulley design
  • One-wire capable: No
  • External regulator included
  • Brand line: Bosch Premium Alternators

Detailed Description

The Bosch AL0921N alternator is a direct replacement charging component for vehicles that require a 12V, 140-amp unit with a short, foot-mounted configuration. It is built with an internal regulator, negative ground setup, and clockwise rotation, making it a practical choice for restoring stable charging performance in modern Audi and Volkswagen electrical systems. The included 6S pulley setup and decoupled clutch pulley support belt-driven accessory operation, while the internal fan helps manage operating temperature.

This part number, AL0921N, also cross-references Bosch OE-style replacement applications and is commonly searched for Audi A3 alternator replacement, Volkswagen Golf GTI alternator replacement, and Volkswagen Atlas alternator replacement. Bosch Premium Alternators are positioned as a premium replacement line focused on tested performance and reliability. Part number AL0921N is also referenced for Audi and Volkswagen charging system service where the original unit matches the listed specifications.

What It Helps Address

  • Battery warning lights caused by weak charging output
  • Low system voltage during driving or idle
  • Dim headlights and unstable electrical performance
  • Charging system failure from a worn alternator
  • Belt-driven accessory charging issues on Audi and Volkswagen platforms

Installation Notes and Fitment

Compatible With 2021 Audi Q3, N/A; 2018-2020 Volkswagen Atlas, N/A; 2020 Volkswagen Atlas Cross Sport, N/A; 2017-2019 Audi S3, N/A; 2017-2019 Volkswagen Golf Alltrack, N/A; 2018-2019 Volkswagen Golf R, N/A; 2017-2019 Volkswagen Golf SportWagen, N/A; 2017-2018 Audi A3, N/A; 2015-2018 Audi A3 Quattro, N/A; 2017-2018 Audi TT Quattro, N/A; 2017-2018 Audi TTS Quattro, N/A; 2017-2018 Volkswagen Golf, N/A; 2017-2018 Volkswagen GTI, N/A.

Verify pulley style, mounting configuration, rotation direction, and electrical connector match before installation. Confirm the vehicle’s charging system diagnosis before replacing the alternator. The AL0921N part number should be matched to the original unit specifications for proper fitment on Audi A3, Volkswagen Golf GTI, and related applications.

Quality Assurance

Bosch manufactures this alternator as a new replacement component and tests it for performance and reliability. The Bosch Premium Alternators line is built to meet the demands of OE-style charging system service on Audi and Volkswagen vehicles.

Related reading

This part fits 30 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelBody TypeLitersCylindersNotes
2021AudiQ3—2.0LL4Alternator (New)
2020VolkswagenAtlas—2.0LL4Alternator (New)
2020VolkswagenAtlas Cross Sport—2.0LL4Alternator (New)
2019AudiS3—2.0LL4Alternator (New)
2019VolkswagenAtlas—2.0LL4Alternator (New)
2019VolkswagenGolf Alltrack—1.8LL4Alternator (New)
2019VolkswagenGolf R—2.0LL4Alternator (New)
2019VolkswagenGolf SportWagen—1.8LL4Alternator (New)
2018AudiA3—2.0LL4Alternator (New)
2018AudiA3 QuattroConvertible2.0LL4Alternator (New)
2018AudiS3—2.0LL4Alternator (New)
2018AudiTT Quattro—2.0LL4Alternator (New)
2018AudiTTS Quattro—2.0LL4Alternator (New)
2018VolkswagenAtlas—2.0LL4Alternator (New)
2018VolkswagenGolf—1.8LL4Alternator (New)
2018VolkswagenGolf Alltrack—1.8LL4Alternator (New)
2018VolkswagenGolf R—2.0LL4Alternator (New)
2018VolkswagenGolf SportWagen—1.8LL4Alternator (New)
2018VolkswagenGTI—2.0LL4Alternator (New)
2017AudiA3—2.0LL4Alternator (New)
2017AudiA3 Quattro—2.0LL4Alternator (New)
2017AudiS3—2.0LL4Alternator (New)
2017AudiTT Quattro—2.0LL4Alternator (New)
2017AudiTTS Quattro—2.0LL4Alternator (New)
2017VolkswagenGolf—1.8LL4Alternator (New)
2017VolkswagenGolf Alltrack—1.8LL4Alternator (New)
2017VolkswagenGolf SportWagen—1.8LL4Alternator (New)
2017VolkswagenGTI—2.0LL4Alternator (New)
2016AudiA3 Quattro—2.0LL4Alternator (New)
2015AudiA3 Quattro—2.0LL4Alternator (New)
Directly replaces or cross-references 4 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
06J903023A06J903023G06K903024A06K903024C