Audi A6/S6 Alternator Air Duct 4B3903423

OEM Part #: 4B3-903-423 (4B3903423)

This page covers one exact OEM part number. Every unit we stocked has sold.

We may be able to get another

Used OEM parts are one-of-a-kind. We sometimes get another when we dismantle a matching vehicle, but we can’t say when — browse what’s in stock now:

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The Audi Alternator Air Duct (OEM part number 4B3903423) is a genuine used OEM component sourced from a donor vehicle. This duct channels cooling air to the alternator on the 4.2L V8 engine found in select Audi models. If the duct is cracked or missing, the alternator can overheat, reducing charging output or causing premature failure—a common issue on these V8s. This is the air intake duct, not the alternator itself.

Specifications

Specifications for Alternator Air Duct 4B3903423
Fits Vehicle ModelA6, S6
Fits Vehicle MakeAudi
OEM Part No4B3-903-423 (4B3903423)
CategoryBattery / Charging / Starting

Compatible Vehicles

Fits 7 vehicle configurations across 1 make, 2000-2004.

Check your specific vehicle before ordering. This list shows year, make, and model. Some years have multiple trims or engines that use different parts, and individual listings may have additional fitment notes (e.g. “with sunroof only”). Review the full variant list below, or message us with your VIN and we’ll confirm the match.

Audi

  • A6 2000-2004 · 5 variants
  • S6 2002-2003 · 2 variants
View all 7 vehicle configurations
Full vehicle fitment list for Alternator Air Duct 4B3903423
Year Make Model Trim Engine Note
2000 Audi A6 Quattro Sedan 4.2L V8
2001 Audi A6 Quattro Sedan 4.2L V8
2002 Audi A6 Quattro Sedan 4.2L V8
2002 Audi S6 Wagon 4.2L V8
2003 Audi A6 Quattro Sedan 4.2L V8
2003 Audi S6 Wagon 4.2L V8
2004 Audi A6 Quattro Sedan 4.2L V8

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