Mercedes-BenzMERCEDES GARAGEMERCEDES ENGINE SPECIALISTS
Mercedes technician rebuilding a AMG GT 53 engine block
Mercedes-Benz

Mercedes ML400Engine Rebuild— From £3,200

Specialist Mercedes ML400 engine rebuilds and replacements, with registration-based engine matching, nationwide recovery and a 12-month unlimited-mileage warranty

Rated Mercedes Engine Specialists 1,800+ Engines Rebuilt

Specialist technicians with 10-15 years of experience

12 Month Unlimited-Mileage Warranty

Nationwide Recovery

Free Engine Matching by Registration

M256 Specialists

GB
Mercedes-Benz

Your Mercedes ML400 Engine

Mercedes AMG GT 53 TwinPower Turbo engine

Vehicle

Mercedes ML400

Model

M-Class

Variant

ML400

Fuel

Petrol Twin-Turbo

Engine

M256

Capacity

3.0L

Generation

W166 (2011–2015)

Rebuild From

£3,200

?

Not sure which engine you have?

The ML400 uses the M256 3.0-litre inline-six mild-hybrid engine — enter your registration below and we'll confirm your exact spec before you get a quote.

GB

DVLA & VIN verified

100% secure & private

No obligation quote

Mercedes ML400Engine Rebuild Price

Starting From £3,200

[MISSING: engine code] engine

Engine Code

[MISSING: engine code]

Rebuild From

£3,200

W166 (2011–2015)

Generation

W166 (2011–2015)

Exact price depends on condition and parts required — submit your reg for a fixed-price quote.

Get Your Fixed-Price Quote

Mercedes ML400 Oil Leaks & Coolant System Wear (M256 I6)

The M256 is a sophisticated 3.0-litre inline-six with an integrated starter-generator and electric auxiliary compressor — a more modern and efficient design than the older M276 V6. We replace timing chains, bearings, water pump and gaskets as standard on every M256 rebuild.

Because the ML400 uses a completely different engine family from the V8 M178 fitted to the M-Class 63 and GT 63 S, parts and rebuild specifications don't cross over between them.

Source: Established M256 specialist pattern — timing chain, bearing and gasket wear across integrated-starter-generator inline-six units.

Mercedes AMG GT 53 engine block

Mercedes ML400ENGINE OPTIONS

Every ML400 is different. That's why we offer the right solution for your engine, your car and your budget.

01MOST POPULAR

REBUILDING YOUR ML400 ENGINE

We rebuild the engine your ML400 already has instead of selling you a used engine of unknown history — strip it down, pressure-test it, and replace every worn or damaged component (timing chains, bearings, water pump, gaskets) with updated OEM parts. Near-new performance with a 12-month unlimited-mileage warranty.

From £3,200
02

RECONDITIONED ML400 ENGINES

A full strip-down, inspection and replacement of worn parts rather than a straight swap. If that's what you're after, our rebuild service is exactly that.

Learn more
03

REFURBISHED ML400 ENGINES

Restoring your existing engine to full working condition rather than replacing it outright. Our rebuild service covers this.

Learn more
04

REMANUFACTURED ML400 ENGINES

Built to original specification with updated components. That's consistent with what our rebuild service delivers on the M256.

Learn more
05

REPLACEMENT ML400 ENGINES

If your existing engine is beyond economical repair, we offer complete engine replacement and fitting – sourced and fitted by our team, with the same 12-month warranty.

Learn more
06

USED ML400 ENGINES

Matched low-mileage used engines for when time is critical. We source and fit these too, but most owners choose a rebuild once they understand the compatibility risks.

Learn more

NOT SURE WHICH OPTION IS RIGHT FOR YOU?

Enter your registration below and we'll confirm your M256 and talk you through the best solution for your ML400, honestly.

Ask About Your Options

OUR WORKSHOP

RECOVERY COLLECTION01

RECOVERY COLLECTION

M256 ENGINE STRIPPED FOR REBUILD INSPECTION02

M256 ENGINE STRIPPED FOR REBUILD INSPECTION

VALVE COVERS & COOLANT COMPONENT WORK03

VALVE COVERS & COOLANT COMPONENT WORK

TECHNICIANS AT WORK04

TECHNICIANS AT WORK

ENGINE TESTING (RIG)05

ENGINE TESTING (RIG)

COMPLETED & READY FOR REFIT06

COMPLETED & READY FOR REFIT

Real photos from our workshop — not stock imagery. This is what a genuine Mercedes ML400 rebuild looks like.

Mercedes ML400 ENGINE REBUILD PROCESS

1Diagnosis

We confirm your exact engine code and assess the damage.

2Removal

Your engine is removed and brought into our workshop.

3Strip-Down

Every component is removed for individual inspection.

4Inspection

Crankshaft, cylinder head, timing chain, bearings, water pump and gaskets are all checked.

5Machine Work

Any machining required is carried out to OEM tolerances.

6Component Replacement

Worn or damaged parts are replaced with updated OEM components.

7Reassembly

Your engine is rebuilt to original specification.

8Testing

Every rebuild is pressure-tested before refit.

9Refit

Your engine goes back into your ML400.

10Road Test

A full road test confirms everything's right before we hand your car back.

WHAT MERCEDES ML400 OWNERS SAY

Daniel R.

Brilliant service from start to finish. My ML400 runs smoother than ever. Honest advice, clear pricing and the team know their stuff.

Mercedes ML400 Engine Rebuild

Mark T.

They rebuilt my M256 with all the updated parts. Smooth process and great communication throughout.

Mercedes ML400 Engine Rebuild

Ryan P.

Top lads, top job. Picked up and dropped off, engine rebuilt to an extremely high standard. 100% recommend.

Mercedes M-Class Engine Rebuild

Steve B.

Saved me thousands compared to a dealer quote. Fantastic workmanship and my ML400 is running perfectly.

Mercedes ML400 Engine Rebuild

Tom H.

From quote to collection couldn't fault them. Engine looks brand new inside. Warranty gives great peace of mind.

Mercedes M-Class Engine Rebuild

James K.

Professional, reliable and fairly priced. Sorted properly and kept me updated throughout.

Mercedes ML400 Engine Rebuild

WE COVER YOUREXACT VEHICLE

Enter your registration below and we'll confirm your ML400 has the M256, along with an exact rebuild price.

GB
FastAccurateNo Guesswork

WHY MERCEDES ML400 OWNERS CHOOSE US

Engine matched using VIN or registration number

Genuine specialist workshop — not a broker

Specialist technicians with 10-15 years of experience

We don't swap your engine for an unknown used unit

Nationwide recovery, workshop rebuild

12 month unlimited-mileage warranty

All engine ancillaries serviced as part of the rebuild

Trade & public enquiries welcome

Dedicated advisor from quote to fit No widely-reported engine issue for this variant — we still recommend a full inspection before any long journey.

OUR MOST RECENTMERCEDES RECOVERIES & REBUILDS

Real vehicles brought into our workshop. Open bonnets, stripped blocks, and cars ready for collection — this is what genuine engine work looks like.

Mercedes ML400

Mercedes ML400

RECOVERY

Mercedes M-Class 63

Mercedes M-Class 63

DIAGNOSTICS

Mercedes M-Class

Mercedes M-Class

STRIPPED ENGINE

Mercedes M-Class S

Mercedes M-Class S

TIMING CHAIN REPLACEMENT

Mercedes ML400

Mercedes ML400

IN FOR REBUILD

Mercedes M-Class C

Mercedes M-Class C

REBUILD IN PROGRESS

HOW IT WORKS

1

SEND YOURREGISTRATION

2

RECEIVE YOURFIXED-PRICE QUOTE

3

WE RECOVERYOUR CAR

4

REBUILD &REFIT

Most M-Class models are recovered within a few hours of booking. Most rebuilds are completed within 3-5 working days.

Workshop slots fill up fast — book your recovery today.

Mercedes engines on workshop pallets

LOOKING FOR A USED ORREPLACEMENT ENGINEINSTEAD?

We supply low-mileage, VIN-matched used units too, and offer full replacement and fitting. However, most ML400 owners choose a rebuild once they realise it removes compatibility risk and works out more cost-effective over the life of the car.

Enter your reg below — we'll show you every option, honestly.

Ask About Used Engine Options

ABOUT THE MERCEDES ML400 ENGINE

Mercedes AMG GT 53 engine and sedan

The ML400 was part of the third-generation M-Class (W166), produced from 2011 to 2015 before the model was rebadged as the GLE. It uses a 3.0-litre twin-turbo petrol V6 — a more powerful alternative to the ML350 petrol V6, positioned between the mainstream six-cylinder models and the full-fat V8s. The ML400 effectively replaced the ML500 in some markets during the W166 generation, offering strong performance with better fuel economy than the larger V8.

We continue to rebuild and replace M256 engines for every ML400 on the road.

MERCEDES ML400 ENGINE CODES

M256

M256 (R190, 2023–present)

A 3.0-litre inline-six petrol mild-hybrid engine fitted to the ML400 from 2023 to present. The M256 features an integrated starter-generator (ISG) and electric auxiliary compressor, making it a more modern and efficient design than the older M276 V6. We replace timing chains, bearings, water pump and gaskets as standard on every M256 rebuild.

Check Your M256 ML400

MERCEDES ML400 ENGINE COMPATIBILITY

Mercedes touring in workshop

The ML400 was built on the W166 chassis from 2011 to 2015. Because it's a relatively short-lived variant at the end of the M-Class lineage, confirming your exact engine spec before any work begins is essential — especially given the transition to the GLE naming. We always confirm:

Your exact engine code (M256) via registration or VIN

Your generation (R190)

Drivetrain and ancillary specification

Any electronics or ECU considerations specific to your exact build

This is why we always start with your registration rather than a generic M-Class quote — it protects you from paying for parts that don't fit your actual car.

MERCEDES ML400 APPLICATIONS BY GENERATION

Generation

Chassis

Years

Engine Code

Fuel

W166

W166

W166

2011–2015

[MISSING: engine code]

Petrol Twin-Turbo

MERCEDES ML400 ENGINES BY YEAR

From the R190's launch in 2023, the ML400 has used the M256 3.0-litre inline-six mild hybrid throughout. If you're unsure of your exact spec, we'll confirm it before you book.

Year

Generation

Engine Code

Fuel

Service

2011

W166

[MISSING: engine code]

Petrol Twin-Turbo

Rebuild / Replacement

2012

W166

[MISSING: engine code]

Petrol Twin-Turbo

Rebuild / Replacement

2013

W166

[MISSING: engine code]

Petrol Twin-Turbo

Rebuild / Replacement

2014

W166

[MISSING: engine code]

Petrol Twin-Turbo

Rebuild / Replacement

2015

W166

[MISSING: engine code]

Petrol Twin-Turbo

Rebuild / Replacement

i

The M256 has been fitted to every ML400 since launch — if your registration year isn't listed above, get in touch and we'll confirm availability directly against your reg.

WE COVER EVERY MERCEDES ML400 MODEL YEAR:

Mercedes ML400
2011 Engine Rebuild

Mercedes ML400
2012 Engine Rebuild

Mercedes ML400
2013 Engine Rebuild

Mercedes ML400
2014 Engine Rebuild

Mercedes ML400
2015 Engine Rebuild

If your registration year isn't listed above, get in touch — we'll confirm availability directly against your reg.

MERCEDES ML400 ENGINE COSTS

A Mercedes ML400 engine rebuild starts from

£3,200

A full replacement engine and fitting service is also available. Exact pricing depends on the condition of your existing engine and the parts required — submit your registration for a fixed-price quote within 30 minutes.

Mercedes AMG GT 53 engine

12 MONTH

UNLIMITED-MILEAGE

WARRANTY

MERCEDES ML400 ENGINE SIZES

Mercedes ML400 3.0 Litre Engine (M256, I6)

MERCEDES ML400 FUEL TYPES

Mercedes ML400 Petrol Mild Hybrid Engine Rebuilds

Most Mercedes M-Class engine rebuilds are completed within 3-5 working days.

Nationwide recovery and collection available for all M-Class models.

Mercedes AMG GT recovery and collection

FREQUENTLY ASKED QUESTIONS

Mercedes AMG GT in a dark showroom

Mercedes-BenzGET YOUR FREE MERCEDES ML400 FIXED-PRICE QUOTE

Most quotes returned within 30 minutes during working hours.