What do you actually pay for when replacing a Mercedes engine? We break down supply costs, labour, ancillaries and hidden extras – with real 2025 UK figures and a worked example so you know exactly what to expect.
The short answer: Supply and fit means the cost of the engine itself (supply) plus the cost to remove the old one and install the new one (fit). For a typical Mercedes OM651 replacement, supply is £2,800–£4,800, labour is £520–£780, and ancillaries add £100–£400 – a total fitted cost of £3,500–£5,600 [EM-QUOTE]. The key is understanding what's included – and what isn't.
Next step: use our Repair vs Replace Calculator to compare options, or read the breakdown below.
In plain terms, supply and fit is the total cost to replace your engine – the engine itself, the labour, and all the bits needed to make it work. But it's not always as simple as it sounds.
The engine itself – purchased from a supplier. It can be:
Supply costs vary wildly – see our comparison guide.
The labour to remove the old engine and install the new one, plus:
Labour rates vary by region – see Labour Rates & Fitting Times.
A typical Mercedes engine replacement quote is made up of four main cost categories. Here's what each includes – and what often gets overlooked.
The core cost – reconditioned, used or rebuilt. Typical supply costs from our 2025 data:
Often includes a 6–24 month warranty.
Based on hours × hourly rate. Our 2025 figures:
Labour rates: indie £65–£85/hr; main dealer £130–£180/hr.
Items often sold separately:
This is the most common hidden cost – ask if it's included.
Items that might be needed depending on your car:
These can double the final bill – ask about them upfront.
Here's the full picture – supply + labour + typical ancillaries – for the most common Mercedes engines. All figures are 2025 UK averages [EM-QUOTE].
| Engine Code | Supply (Recon) | Labour | Ancillaries & Fluids | Total Fitted Cost |
|---|---|---|---|---|
| OM651 | £2,800–£4,800 | £520–£780 | £150–£300 | £3,500–£5,600 |
| OM654 | £3,000–£5,000 | £520–£780 | £150–£300 | £3,700–£5,800 |
| OM642 | £3,200–£5,500 | £650–£910 | £200–£400 | £4,000–£6,400 |
| M276 | £3,800–£6,500 | £780–£1,040 | £200–£400 | £4,600–£7,500 |
| M278 | £5,000–£8,000 | £910–£1,170 | £300–£600 | £6,200–£9,800 |
| M157 | £6,000–£10,000 | £1,040–£1,430 | £300–£600 | £7,400–£12,000 |
| M177 | £8,000–£14,000 | £1,040–£1,430 | £400–£800 | £9,400–£16,200 |
| M275/M279 (V12) | £10,000–£20,000+ | £1,300–£1,950 | £600–£1,200 | £12,000–£23,000+ |
Labour based on indie rates at £65/hr. Main dealer costs are 40–60% higher. Ancillary costs are estimates – always confirm what's included in your quote.
A real breakdown of a typical OM651 engine replacement. Here's exactly where the money goes.
A supply-and-fit quote is only as good as what it includes. Here are the questions to ask every specialist before you commit.
Is it reconditioned, used or rebuilt? What warranty is included? Are gaskets, seals and timing chain included?
Ask for the hourly rate and the number of hours estimated. Compare this to our labour guide to see if it's fair.
Turbo, injectors, DPF, clutch – these are often not included. Ask upfront to avoid a surprise bill mid‑job.
Most specialists offer a warranty on the fitted work – typically 6–24 months. Make sure it's in writing.
Never accept a single lump-sum figure. An itemised quote allows you to compare like-for-like and spot missing items.
Supply and fit means the cost of the engine itself (supply) plus the labour to remove the old engine and install the new one (fit). It usually also includes fluids and basic gaskets, but may not include ancillaries like turbo, injectors or clutch.
Costs vary by engine: OM651 £3,500–£5,600 fitted, OM642 £4,000–£6,400, M276 £4,600–£7,500, M177 £9,000–£15,400, V12 M275/M279 £12,000–£23,000+ fitted. These figures include supply, labour and basic ancillaries [EM-QUOTE].
Turbochargers, injectors, DPF, clutch, and major cooling system components are often not included. These can add £500–£3,000 to the final bill – always ask if they're included or extra.
Because labour, fluids, gaskets, seals and ancillaries all add to the total. For an OM651, supply is £2,800–£4,800, but fitted cost is £3,500–£5,600 – labour and ancillaries add £700–£1,000.
Independents are typically 40–60% cheaper and often have more Mercedes-specific experience. Main dealers are more expensive but may be required for warranty or service history reasons. See our labour rates guide for full comparison.
Yes – some specialists will fit an engine you supply, but many won't warranty the work. You also lose the supply warranty. It's usually better to let the specialist source the engine so they stand behind the whole job.
Genuine Enquiry DataBuilt from 24,650 real 2025 UK engine enquiries, including over 5,000 Mercedes-specific records.
Fully Disclosed MethodWe publish exact costs and explain what's included – no hidden agendas.
15+ Vetted Mercedes SpecialistsEvery recommendation routes to a specialist who works on these engines daily.
100% IndependentNo sponsors, no manufacturer influence – we tell you the real costs.
Compare itemised quotes from our vetted specialist network – no hidden fees, no surprises.
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