Alternator replacement cost UK
fitted at an independent garage · parts and labour included
- Pulley only £80–£190
- Charging test often free
- Typical time 1–3 h
An alternator replacement costs £250–£720 at an independent garage, parts and labour included. But hold on: a free charging-system test settles first whether you need one at all — a flat battery, a tired starter and a failed £80–£190 alternator pulley all impersonate a dead alternator. Healthy charging reads 13.8–14.8V with the engine running. Test first, match your symptom below, then compare live quotes.
Estimates for a typical example of each model. Stop-start cars with smart charging may need battery coding — see below. Final quotes come from garages — we may earn a commission when you book through our partners, at no cost to you.
Battery, starter or alternator? Match your symptom first
Three parts share one crime scene, and they’re priced £100, £250 and £500 apart — so the diagnosis order matters more here than almost anywhere on this site. Find your symptom, then let a free test confirm it before any part is bought:
| What’s happening | Prime suspect | Why |
|---|---|---|
| Nothing at all when you turn the key — no lights, no clicks | Battery (or a connection) | Totally dead electrics point at the cheapest fix first: a flat/failed battery or corroded terminal |
| Lights work, single loud click, engine doesn’t turn | Starter motor | Power is there; the starter isn’t engaging — a different repair from this page |
| Cranks slowly, starts reluctantly, especially cold mornings | Battery first, alternator second | A tired battery cranks slowly — but so does a good battery an alternator isn’t refilling |
| Battery warning light on while driving | Alternator (or its belt/pulley) | That light means “not charging” — the battery is now running the car on borrowed time |
| Brand-new battery flat again within days | Alternator | The clearest alternator tell there is — replacing batteries into a dead charger is a subscription |
| Starts fine, dies after 20–60 minutes of driving | Alternator | The engine ran off the battery until it emptied — charging failed, storage didn’t |
The tiebreaker costs nothing: most garages and fast-fit chains test the charging system free. Healthy: 12.4–12.7V engine off, 13.8–14.8V running.
Alternator replacement cost by make and model
Prices below are for an independent garage fitting a quality reconditioned or aftermarket unit (Bosch, Valeo, Denso remans — the factory names), parts and labour included, with the drive belt checked as part of the job.
| Car | Alternator, fitted | Pulley only | Typical time |
|---|---|---|---|
| Ford Fiesta | £250–£450 | £80–£140 | 1–2 h |
| Ford Focus | £270–£480 | £80–£140 | 1–2 h |
| Vauxhall Corsa | £250–£460 | £80–£140 | 1–2 h |
| Vauxhall Astra | £270–£480 | £80–£140 | 1–2 h |
| Volkswagen Golf | £290–£520 | £90–£160 | 1.5–2.5 h |
| Volkswagen Polo | £270–£490 | £90–£160 | 1–2 h |
| Nissan Qashqai | £300–£540 | £90–£160 | 1.5–2.5 h |
| Nissan Juke | £290–£520 | £90–£160 | 1.5–2.5 h |
| Mercedes A-Class | £380–£680 | £110–£190 | 2–3 h |
| BMW 1 Series | £380–£680 | £110–£190 | 2–3 h |
| BMW 3 Series | £400–£720 | £110–£190 | 2–3 h |
| Audi A3 | £350–£640 | £100–£180 | 2–3 h |
| Honda Civic | £290–£530 | £90–£160 | 1.5–2.5 h |
| Toyota Yaris (petrol) | £260–£470 | £80–£150 | 1–2 h |
| Kia Sportage | £320–£570 | £100–£170 | 1.5–2.5 h |
Estimates for independent garages. Main dealers typically charge around 50% more. Yaris hybrids have no conventional alternator — the hybrid system charges the battery instead. Final quotes come from garages.
What affects the price of an alternator replacement
Access decides the labour. An alternator sitting on top of a small petrol engine is an hour’s work; one wedged low on a packed diesel bay — with the intake, a driveshaft or an engine mount in the way — is three. Same unit, different afternoon, and it’s why the ranges above aren’t badge snobbery.
Recon vs new moves the parts bill £100+. A quality remanufactured exchange unit from the factory names (Bosch, Valeo, Denso) is the standard, sensible fit for an out-of-warranty car — new OEM adds £100–£200 for little real-world gain. The unit to refuse is the unbranded marketplace special: its regulator quality is a lottery your car’s electronics play too.
Stop-start cars add a coding step. Smart charging systems manage the alternator through the ECU and expect a specific battery type (AGM or EFB) registered to the car — so the quote should include diagnostic time, and any battery replaced alongside must be coded in, not just dropped in. The usual rate maths applies on top — see the full comparison.
The £100 suspect: the overrunning alternator pulley
Most modern alternators drive through an overrunning (freewheel) pulley — a one-way clutch that smooths belt vibration. It wears out years before the alternator behind it, and when it fails it stages a convincing alternator death: charging drops, the battery light flickers, the belt chirps and rattles at idle and on shutdown.
The test takes a minute with the belt off — a healthy pulley locks one way and freewheels the other — and the fix is £80–£190 fitted. It’s this page’s version of the drop link on our suspension guide: the cheap, common part that gets billed as the expensive one behind it. Before signing off a full alternator, the house question: “was the pulley checked separately?”
6 symptoms of a failing alternator
Alternators rarely die without notice — the electrical system broadcasts the decline. The signs, each with what it means for the bill:
- The battery warning light
The red battery symbol means the charging system has stopped — from this moment the car runs on whatever the battery holds.
Cost signal: could be the £500 unit, the £100 pulley, or a £40 belt — the free voltage test sorts them before money moves. - Dimming and flickering lights
Headlights that dim at idle and brighten with revs, a flickering dash — voltage sagging as the alternator loses its grip.
Cost signal: the classic early warning. Book the test now, on your schedule, not the breakdown lane’s. - A new battery, flat again
The unambiguous one: a healthy new battery emptied within days means nothing is refilling it.
Cost signal: stop buying batteries — and have the garage test whether the deep discharges damaged this one too. - Whining or grinding from the front of the engine
A whine rising with revs is alternator bearings; a rattle at idle or a chirp on shutdown is often the overrunning pulley.
Cost signal: the sound splits the bill — bearings mean the unit, the shutdown chirp means the £80–£190 pulley. - Electrical gremlins everywhere
Wipers slowing, radio resetting, warning lights flickering in chorus — low system voltage confuses every module at once.
Cost signal: resist chasing each gremlin separately — one charging fault is impersonating five repairs. - Burning rubber smell
A seized alternator or locked pulley drags the drive belt across it until the belt burns — smell first, snap second.
Cost signal: urgent — a snapped belt on many engines also drives the water pump, and that’s an overheating story you don’t want.
Can I keep driving with a failing alternator?
Only as far as the battery lasts — typically 20 to 60 minutes from the moment the light comes on, less at night with headlights, wipers and heater drinking the reserve. The car doesn’t wind down politely: injection and ignition quit when voltage drops below their threshold, wherever you happen to be. So treat the light as a routing instruction: switch off everything electrical you can, drive directly to a garage or home, and don’t switch the engine off en route — restarting is the single biggest withdrawal from a battery that isn’t being repaid.
Two follow-ups people learn the hard way: a jump start is a loan, not a fix — the car dies again down the road; and a battery that’s been deep-discharged by an alternator failure is often collateral damage, so have its health tested after the repair rather than discovering it on the next frosty morning.
Independent garage vs main dealer vs fast-fit chain
Alternators are everyday work for all three garage types — and the free charging test most fast-fits offer makes them a genuinely useful first stop even if you book the repair elsewhere.
| Independent garage | Main dealer | National fast-fit chain | |
|---|---|---|---|
| Charging system test | Often free with the job | Diagnostic fee £50–£120 | Usually free |
| Alternator, fitted | £250–£720 (baseline) | +50%, new OEM unit | Close to independent |
| Parts fitted | Bosch / Valeo / Denso reman or aftermarket | Genuine new | Own-brand or aftermarket |
| Warranty on the job | Typically 12 months | 12–24 months | 12 months, honoured nationwide |
| Best for | Pulley-first diagnosis, awkward-access cars | Stop-start systems, coding, warranty cars | The free test, batteries, simple swaps |
How to pay less on an alternator
Take the free test first. Voltage settles the battery-starter-alternator triangle in five minutes at no cost — the best-value diagnostic in motoring, and the reason nobody should ever buy this part on a hunch.
Ask about the pulley before the unit. The £80–£190 overrunning pulley fails first and fakes the symptoms — a minute’s check with the belt off, and the house question above.
Fit a factory-name reman, and the belt while it’s off. Bosch, Valeo and Denso remanufacture their own units; the drive belt costs £20–£40 with zero extra labour during the job and £100+ as a separate visit later.
Test the battery after the repair. Deep discharge from the failure often halves its remaining life — better a £15 test now than a no-start in December with a fresh alternator watching innocently.
Everyday job, every garage does it — which is exactly when quotes spread £100+. Compare before you book.
Compare live quotesAlternator FAQ
How much does an alternator replacement cost in the UK?
£250–£720 at an independent garage, parts and labour included — mainstream cars at £250–£540 with a quality reconditioned unit, premium cars at the top. An overrunning pulley alone is £80–£190, and main dealers charge roughly 50% more with new OEM units.
How do I know if it’s the battery or the alternator?
Battery faults show at startup (dead electrics, slow cranking); alternator faults show while running (battery light, dimming lights, dying after 20–60 minutes). The unambiguous tell: a new battery flat again within days. A free charging test settles it — 13.8–14.8V running is healthy.
What are the symptoms of a failing alternator?
The battery warning light, headlights dimming at idle, repeated flat batteries, whining or grinding from the front of the engine, electrical gremlins across multiple systems, and in late stages a burning-rubber smell from a dragging belt. Each maps to a different line on the bill — see the guide above.
Can I drive with a failed alternator?
Only on the battery’s reserve — typically 20–60 minutes, less at night. Switch off everything electrical you can, drive straight to a garage or home, and don’t stop the engine on the way: a restart is the biggest single drain on a battery nothing is refilling.
How long should an alternator last?
Typically 100,000–150,000 miles, and many outlast the car. The overrunning pulley on its nose is the weak link, often failing years earlier — which is why a “failing alternator” past 80,000 miles deserves a pulley check before a unit is quoted.
Is a reconditioned alternator OK?
From the factory names — Bosch, Valeo, Denso remanufacture their own units — yes, it’s the standard sensible fit for an out-of-warranty car, £100–£200 under new with a 12–24 month warranty. The one to avoid is the unbranded marketplace unit, whose regulator quality your car’s electronics get to discover.
What is an overrunning alternator pulley?
A one-way clutch pulley on the alternator’s nose that smooths belt vibration. It wears out before the alternator, and its failure — flickering charge, rattle at idle, a chirp when you switch off — convincingly impersonates alternator death. Fixed alone for £80–£190; always worth ruling out first.
Do stop-start cars need anything special?
Yes — smart charging systems are ECU-controlled and expect a specific AGM or EFB battery registered to the car. The alternator job should include diagnostic adaptation, and any battery fitted alongside must be coded in, not just connected. Budget the diagnostic line; it’s a real step, not padding.
What does a whining alternator mean?
A whine that rises with engine revs points at the alternator’s internal bearings — the unit itself. A rattle at idle or a chirp at shutdown points instead at the overrunning pulley. The sound effectively pre-writes the quote: bearings £250–£720, pulley £80–£190.
Will a jump start fix an alternator problem?
No — a jump start borrows charge, it doesn’t create any. If the alternator has failed, the car dies again as soon as the borrowed charge runs out, possibly somewhere worse. Jump it only to reach the garage, and get the charging system tested the same day.
Will a failing alternator fail the MOT?
Not directly — the MOT doesn’t test the charging system, and the battery light isn’t an inspected warning lamp. It’s another item on the list of things a fresh pass says nothing about, alongside the clutch and cambelt — and another reason the light deserves your attention, because no tester will force it.
Will an alternator replacement come with a warranty?
Yes — typically 12 months or 12,000 miles on parts and labour at an independent, 12–24 months at a dealer, and factory-name remans commonly carry their own 2-year parts warranty. Keep the invoice with the unit’s serial noted; reman warranties are claimed against it.