Peugeot 508 Alternator: Specs, Fitment & Common Faults

On the 508, a whining noise that gets louder under load is often the alternator's clutch pulley seizing, not the alternator itself failing — worth confirming before a costly replacement.

Illustration for editorial purposes

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OEM Part Number: confirm via VIN — alternators (aftermarket) Bosch 0 986 082 240 / Valeo 444706

Accuracy note: Covers the Peugeot 508 (2011-2018) as listed in the UK aftermarket catalogues. Alternators are sold by output (amps), pulley type and plug, and the same model usually has two or three units depending on engine, start-stop and the electrical load of the trim — a 120 A unit on a car built for 150 A will undercharge, and a rigid pulley on a car designed for a freewheel clutch pulley will shred belts. The references below are UK aftermarket catalogue listings for this generation, labelled by brand; many are remanufactured exchange units that carry a core charge until the old alternator is returned. Genuine numbers are shown only where a listing quotes one. Check the amp rating, pulley and plug stamped on the old unit, or confirm via VIN, before ordering.

Alternators (aftermarket)	Bosch 0 986 082 240 (150 A, freewheel pulley, 6 ribs, 54.5 mm, remanufactured exchange, plug 132, core charge £50.24, excludes vacuum-pump versions); Valeo 444706 (150 A, freewheel pulley, 6 ribs, 54 mm, remanufactured exchange with deposit, B+/COM plug, core charge £50.24); Valeo 439845 (180 A, rigid belt pulley with V-ribbed pulley, 6 ribs, 52 mm, new, stop-start vehicles only); Valeo 439864 (210 A, rigid belt pulley with V-ribbed pulley, 6 ribs, 53 mm, new, stop-start vehicles only); Valeo 440999 (180 A, rigid belt pulley with V-ribbed pulley, 6 ribs, 52 mm, remanufactured exchange, core charge £152.37, stop-start vehicles only); Lucas LRC00004 (180 A, multi-rib pulley, 6 ribs, 51.5 mm, remanufactured, plug 0292, core charge £75.36); AS-PL A3585 (210 A, rigid pulley, 7 ribs, 52 mm, new, PL_5100 plug, Valeo type).
Outputs & variants	The 508 is listed with 120 A, 150 A, 180 A and 210 A alternators. The 120 A units fit the 1.6 VTi petrol; the 150 A 54 mm freewheel units are the standard 1.6 HDi, 2.0 HDi and 1.6 THP fitment without stop-start; the 180 A and 210 A Valeo units with a rigid 52-53 mm pulley are the e-HDi and BlueHDi stop-start alternators, with the 210 A unit (OE 439864) serving the 2.0 HDi and 2.2 HDi.
Genuine (OE) numbers quoted	439864 (AS-PL A3585 (VALEO), stop-start).
Fitment notes	The stop-start alternators are a reversible starter-generator design and cannot be replaced by a standard freewheel unit, so confirm the car's specification first; the Valeo 440999 exchange unit carries a £152.37 core charge and the Lucas LRC00004 £75.36, refunded on return of the old part.

A Genuine, Well-Documented Cause Worth Checking First: The Clutch Pulley — Peugeot 508 Alternator

A well-documented, genuinely useful thing to check before assuming the alternator itself has failed: a groaning or whining noise from the belt area, particularly noticeable as engine revs rise, is very often the alternator's clutch pulley seizing up rather than the alternator's internal charging components failing. One documented case describes exactly this pattern — a loud whine assumed to be a cambelt or water pump issue, which disappeared entirely once the drive belt was removed, confirming the noise was coming from something belt-driven rather than the engine internals. Removing the belt and turning the pulley by hand in both directions is a genuinely useful test: it should lock solid in the normal drive direction and spin freely the other way — if it doesn't behave this way, the clutch pulley has failed rather than anything inside the alternator.

Worth knowing if you have a persistent charging fault rather than a noise: Peugeot's "smart" alternators are controlled by the engine ECU via a LIN-bus signal wire rather than charging at a fixed voltage, and a software-related recall (reference HNZ) has been confirmed on related models for exactly this kind of charging disruption. If disconnecting the alternator's signal connector restores normal charging, this points toward a software or ECU communication fault rather than the alternator itself — worth checking before authorising an expensive replacement.

Peugeot 508 Alternator: Often Blamed on the Battery Instead

On the Peugeot 508, a failing alternator and a simply weak battery share almost the same symptom set at first: dim lights, sluggish starts, charge that won't hold. Mixing the two up is common, which is why plenty of people replace the battery only to find themselves back at the garage shortly after.

Peugeot 508 Alternator: Watch: Replacing It

🎬 Watch: How To Replace The Alternator On The 1.6HDi Peugeot 508

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Mk1 508 1.6 HDi

Before you buy: alternator output rating varies by engine size and trim, particularly on cars with more onboard electronics. Always confirm against your VIN before ordering.

Peugeot 508 Alternator: What It Does

The Peugeot 508's electrical systems and battery charging both depend on the alternator generating electricity whenever the engine runs. If it's healthy, the battery's job shrinks down to starting the engine and handling brief surges in demand, not powering everything else on its own.

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Peugeot 508 Alternator: Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Alternator Guide for symptoms to watch for (plus a genuinely useful two-minute test to confirm it's not the battery instead), confirming the right amperage and fitment against your VIN, and which brands are worth trusting.

More Peugeot Alternator

The same part, covered across other Peugeot models.