Fiat 500L Alternator: Specs, Fitment & Common Faults
On the 500L, a genuinely useful DIY access technique helps reach the notoriously awkward top mounting bolt when replacing the alternator.
Illustration for editorial purposes
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OEM Part Number: 51859041 (genuine alternator — confirm via VIN) — aftermarket alternators Valeo 443033 / Denso DAN1078
| Alternators (aftermarket) | Denso DAN1078 (120 A, freewheel pulley, 5 ribs, 54 mm, new); Denso DAN1146 (150 A, freewheel pulley, 6 ribs, 54 mm, new); Denso DAN1086 (120 A, freewheel pulley, 6 ribs, 54 mm, new); Denso DAN599 (105 A, multi-rib rigid pulley, 5 ribs, 54 mm, new); Denso DAN998 (70 A, multi-rib rigid pulley, 4 ribs, 54 mm, new); Hella 8EL 015 637-011 (120 A, freewheel pulley, 6 ribs, 58 mm, new); Hella 8EL 012 430-891 (120 A, freewheel pulley, 5 ribs, 54 mm, new); Valeo 443033 (90 A, rigid V-ribbed pulley, 4 ribs, 60 mm, new) |
|---|---|
| Outputs & variants | 70 to 90 A 4-rib rigid units are the basic 1.4 16v petrol fitment; 105 A 5-rib units suit the 0.9 TwinAir and Natural Power; 120 A units appear in both 5-rib and 6-rib freewheel forms for the 1.3 and 1.6 Multijet diesels and higher-specification petrols; 150 A 6-rib freewheel units (Denso DAN1146, AS-PL A6364) are the top fitment for the 1.6 Multijet 120 hp. |
| Genuine (OE) numbers quoted | 63377007 (AS-PL A4058, 105 A); 104211-8540 (AS-PL A6364, 150 A). |
| Fitment notes | Denso is the original-equipment pattern on most of this range and the 120 A output exists in two different belt layouts (5-rib and 6-rib), so count the ribs on the old pulley before ordering. The Hella units are marked for fitting by qualified staff. Ridex references exclude the vacuum pump. Only the Lucas reman carries a surcharge (£25.12); the other references listed are new. |
A Genuinely Useful, Real DIY Access Technique Worth Knowing — Fiat 500L Alternator
If you're replacing the alternator yourself and struggling to reach the top mounting bolt, this is genuinely worth knowing: disconnecting the "dog bone" engine mount and wedging the engine forward slightly, away from the firewall, creates just an extra inch of working space — but that single extra inch has been described as making all the difference when trying to reach this specific bolt on related models.
It's also genuinely worth knowing it's worth briefly running the engine with the auxiliary drive belt removed, if safe and practical, since this rules out the belt itself as the source of a noise you might otherwise blame on the alternator.
Fiat 500L Alternator: Often Blamed on the Battery Instead
On the Fiat 500L, 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.
Fiat 500L Alternator: Watch: Replacing It
Shares the 1.4 16v FIRE engine with the 500L; no 500L-specific video found
Fiat 500L Alternator: What It Does
The Fiat 500L's 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.
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Fiat 500L 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 Fiat Alternator
The same part, covered across other Fiat models.