Mercedes Sprinter Alternator 180A – Genuine Mercedes-Benz | NCV3 3.0L OM642 | #6421540402OE (2010–2018)

A failing alternator on a NCV3 Sprinter drains the battery under load, dims the lights at idle, and eventually leaves the van with a dead electrical system — often without warning until voltage drops below the point where the ECU can maintain normal operation. This is the Genuine Mercedes-Benz 180-amp alternator for NCV3 Sprinters equipped with the 3.0L OM642 diesel engine, a direct replacement that restores full charging output and stable electrical system performance.

What This Part Does

The alternator is driven by the serpentine belt and converts mechanical energy from the engine into the electrical current that charges the battery and powers every system on the van — from the ECU and fuel injectors to the lights, HVAC blower, and any upfitted electrical equipment. At 180 amps it provides the charging capacity the OM642-equipped Sprinter requires for its engine management, BlueTec emissions system, and vehicle electrical loads. When the alternator's diode pack, voltage regulator, brushes, or bearings fail, charging voltage drops or becomes erratic — causing battery drain, voltage-sensitive fault codes from the ECU, and eventually a no-start.

Common Symptoms of a Failing Alternator

• Battery warning light or low voltage warning in the instrument cluster
• Headlights that dim at idle and brighten under acceleration
• Battery that drains overnight despite being healthy
• Voltage-related fault codes or electrical system warnings after extended idling
• Whining or grinding from the alternator pulley area under load
• Repeated battery failures that return after replacement

When to Replace

Replace when charging voltage is confirmed below specification under load and the alternator is diagnosed as the fault source. Always replace the serpentine belt and tensioner if due for service, as these share the same labor access.

NCV3 OM642 Specific — VIN Verification Required

This alternator is for NCV3 Sprinters equipped with the 3.0L OM642 diesel engine. Always verify your engine code and VIN before ordering. Contact us and we'll confirm fitment before you buy.

Fitment

• 2010–2018 Mercedes-Benz Sprinter 2500 / 3500 – 3.0L OM642 (NCV3/W906)
• 2010–2018 Freightliner Sprinter 2500 / 3500 – 3.0L OM642 (NCV3)

✔ 180-amp output — verify your van's alternator amperage rating before ordering
✔ Genuine Mercedes-Benz OEM unit

Part Numbers

• Mercedes OEM: 6421540402 / A6421540402 / 642-154-04-02
• Manufacturer: Genuine Mercedes-Benz
• SKU: 6421540402OE