Peugeot 108 Alternator: Specs, Fitment & Common Faults

On the 108, a whining noise at idle that gets louder under load is often the alternator's clutch pulley seizing, not the alternator itself failing.

Illustration for editorial purposes

OEM Part Numbers

Accuracy note: we weren't able to verify a confident Peugeot 108 alternator part number at the time of writing. Please confirm the correct part via a Peugeot dealer or parts specialist using your VIN.

A Genuine, Well-Documented Cause Worth Checking First: The Clutch Pulley

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.

Often Blamed on the Battery Instead

A weak battery and a failing alternator produce almost identical symptoms at first — dim lights, slow starts, a car that won't hold charge — which is exactly why so many people replace the battery, only to be back at the garage a few weeks later with the real culprit untouched.

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.

What It Does

The alternator generates electricity while the engine runs, charging the battery and powering the car's electrical systems directly. A healthy alternator means the battery is mostly there for starting the engine and covering brief demand spikes — not for actually running the car's electronics on its own.

Fitment & Compatibility

Alternator output rating differs between engine sizes and trims of the 108, with higher-spec cars carrying more onboard electronics that demand a higher-output unit. Always confirm the exact part number for your specific engine before ordering. Whether you're sourcing a replacement alternator for your Peugeot 108 from a dealer, specialist, or online marketplace, always check compatibility against your registration or VIN before buying.

Common Faults

Symptoms of Failure

Dashboard battery warning light — the most direct signal, though it can also indicate a battery or wiring fault rather than the alternator itself.
Dimming or flickering headlights — especially noticeable at idle or low revs, when the alternator struggles most to keep up with demand.
Whining or grinding noise from the engine bay — can point to a worn bearing inside the alternator itself.
Battery repeatedly going flat — if a new battery keeps discharging, the alternator is often the real cause rather than the battery being faulty again.

DIY Replacement Difficulty

This is a moderate DIY job on most versions, though access varies significantly depending on engine layout — some require removing other components to reach the alternator, which can extend the job considerably. Expect 1–3 hours for an experienced home mechanic depending on access, or around an hour of labour at a garage with the right tools.

OEM vs. Aftermarket

Reputable aftermarket alternators are generally a safe, cost-effective alternative to OEM parts, provided they match the correct output rating for your specific trim. Remanufactured units from established brands are also a solid middle-ground option, often coming with a warranty comparable to new parts at a lower price.

More Peugeot Alternator Guides

The same part, covered across other Peugeot models.