Hyundai i30 Alternator: Specs, Fitment & Common Faults

On the i30, resting and running voltage figures genuinely reveal whether the alternator is charging correctly.

Illustration for editorial purposes

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OEM Part Number: 37300-03350 (as quoted in catalogue listings — confirm via VIN) — aftermarket alternators AS-PL A9436S / Ridex Reman 4G1774R

Accuracy note: Covers the Hyundai i30 (2017-) 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)	AS-PL A9436S (130 A, freewheel clutch pulley, 6 ribs, 58 mm, new, PL_3307 plug); AS-PL A6793S (150 A, freewheel clutch pulley, 6 ribs, 54 mm, new, PL_3307 plug); AS-PL A3515S (90 A, rigid belt pulley, 5 ribs, 57.5 mm, new, PL_3307 plug); AS-PL A9443S (90 A, rigid belt pulley, 5 ribs, 58 mm, new, PL_3307 plug); Rotovis 9091461 (130 A, freewheel clutch pulley, 6 ribs, 58 mm, reman, COM plug); Rotovis 9091468 (130 A, freewheel clutch pulley, 6 ribs, 58 mm, reman, C/L/FR plug); Ridex Reman 4G1774R (90 A, rigid belt pulley, 5 ribs, 58 mm, reman exchange, B+ M8, excludes vacuum pump, core charge GBP 30.14); Walker WAL01400 (150 A, freewheel clutch pulley, 6 ribs, 57 mm, new, COM/LIN2 plug, core charge GBP 50.24).
Outputs & variants	Outputs run 90 A, 120 A, 130 A and 150 A. The 1.4 MPi and 1.5 petrols take the 90 A five-rib rigid-pulley unit; the 1.0 and 1.4 T-GDi petrols and 1.6 CRDi diesels take 120 A to 130 A on a six-rib 57 to 58 mm freewheel clutch pulley; 150 A units with a 54 to 57 mm freewheel pulley cover the higher-spec cars and the i30 N. The 48 V mild-hybrid versions from 2020 use a separate 200 A or 230 A seven-rib starter-generator.
Genuine (OE) numbers quoted	AS-PL A3515S quotes 37300-03350; AS-PL A9443S quotes 37300-03815; AS-PL A6793S quotes 104211-9700; AS-PL A9436S quotes 37300-03AA0.
Fitment notes	Work from the amperage and rib count on the old unit, because 90 A five-rib rigid and 130 A six-rib freewheel units both fit the same body shell; the 48 V units are not interchangeable with 12 V alternators and need high-voltage precautions; Walker, Stardax and Ridex exchange units carry refundable core charges; the Ridex reman unit excludes engines with an alternator-driven vacuum pump.

A Genuinely Useful Diagnostic Benchmark Worth Knowing — Hyundai i30 Alternator

If you're trying to determine whether the alternator is genuinely at fault, this is worth knowing: with the engine off, battery voltage should read between roughly 12.4 and 12.7 volts. Once started, this should rise to between roughly 13.7 and 14.7 volts if charging correctly. If a warning light appears while driving, turning off every accessory you safely can and seeing if the warning clears tells you whether there's still enough charging capacity to get you somewhere safely.

A genuinely important safety warning worth knowing before attempting a DIY alternator swap: one documented case saw the positive battery cable briefly make contact with the exhaust manifold shield during removal, causing a spark. It's worth fully disconnecting the battery's negative terminal first and routing cables carefully away from hot exhaust components.

It's also worth knowing that on some models, the fuse protecting the alternator circuit isn't a conventional, easily replaceable fuse at all, but a shunt in a different physical location.

Hyundai i30 Alternator: Often Blamed on the Battery Instead

On the Hyundai i30, dim lights, slow starts, a battery that won't hold charge — these symptoms point equally to a weak battery or a failing alternator, and that overlap is why so many replacements target the wrong part first, with the real problem only surfacing weeks later.

Hyundai i30 Alternator: Watch: Replacing It

🎬 Watch: How to install alternator on a 2017 Hyundai Elantra (sister (hyundai elantra ad))

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same engine family and layout; no i30 PD video found

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.

Hyundai i30 Alternator: What It Does

Electricity generation while the Hyundai i30's engine is running is the alternator's job, charging the battery and directly powering the electrical systems. When it's working properly, the battery mostly just handles engine starting and short demand spikes, not day-to-day electrical load.

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Hyundai i30 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 Hyundai Alternator

The same part, covered across other Hyundai models.