Mercedes GLC400dEngine Rebuild— From £2,800
Specialist Mercedes GLC400d 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
Your Mercedes GLC400d Engine
Vehicle
Mercedes GLC400d
Model
GLC-Class
Variant
GLC400d
Fuel
Diesel MHEV
Engine
OM656
Capacity
3.0L I6
Generation
X254 (2022–present)
Rebuild From
£2,800
Not sure which engine you have?
The GLC400D 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.
DVLA & VIN verified
100% secure & private
No obligation quote
Mercedes GLC400dEngine Rebuild Price
Starting From £2,800
Engine Code
OM656Rebuild From
£2,800
Generation
X254 (2022–present)
Exact price depends on condition and parts required — submit your reg for a fixed-price quote.
Mercedes GLC400d 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 GLC400D uses a completely different engine family from the V8 M178 fitted to the GLC-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 GLC400dENGINE OPTIONS
Every GLC400D is different. That's why we offer the right solution for your engine, your car and your budget.
REBUILDING YOUR GLC400D ENGINE
We rebuild the engine your GLC400D 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 £3,200RECONDITIONED GLC400D 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 moreREFURBISHED GLC400D ENGINES
Restoring your existing engine to full working condition rather than replacing it outright. Our rebuild service covers this.
Learn moreREMANUFACTURED GLC400D ENGINES
Built to original specification with updated components. That's consistent with what our rebuild service delivers on the M256.
Learn moreREPLACEMENT GLC400D 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 moreUSED GLC400D 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 moreNOT 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 GLC400D, honestly.
Ask About Your Options
OUR WORKSHOP
01RECOVERY COLLECTION
02M256 ENGINE STRIPPED FOR REBUILD INSPECTION
03VALVE COVERS & COOLANT COMPONENT WORK
04TECHNICIANS AT WORK
05ENGINE TESTING (RIG)
06COMPLETED & READY FOR REFIT
Real photos from our workshop — not stock imagery. This is what a genuine Mercedes GLC400d rebuild looks like.
Mercedes GLC400d ENGINE REBUILD PROCESS
WHAT MERCEDES GLC400D OWNERS SAY
WE COVER YOUREXACT VEHICLE
Enter your registration below and we'll confirm your GLC400D has the M256, along with an exact rebuild price.
WHY MERCEDES GLC400D OWNERS CHOOSE US
Engine matched using VIN or registration number — confirms your OM656 spec before you're quoted
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
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 GLC400d
RECOVERY
Mercedes GLC-Class 63
DIAGNOSTICS
Mercedes GLC-Class
STRIPPED ENGINE
Mercedes GLC-Class S
TIMING CHAIN REPLACEMENT
Mercedes GLC400d
IN FOR REBUILD
Mercedes GLC-Class C
REBUILD IN PROGRESS
HOW IT WORKS
SEND YOURREGISTRATION
RECEIVE YOURFIXED-PRICE QUOTE
WE RECOVERYOUR CAR
REBUILD &REFIT
Most GLC-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.
LOOKING FOR A USED ORREPLACEMENT ENGINEINSTEAD?
We supply low-mileage, VIN-matched used units too, and offer full replacement and fitting. However, most GLC400D 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.
ABOUT THE MERCEDES GLC400D ENGINE
The GLC400d was introduced with the X254 generation of the GLC-Class in 2022, slotting in as the top diesel option above the GLC220d and GLC300d. It uses the OM656 — a 3.0-litre inline-six diesel that's part of Mercedes' newer modular engine family, fitted with mild-hybrid technology from launch. Unlike the earlier X253 generation's diesel range (which relied on four-cylinder OM651 and OM654 units), the X254 GLC400d uses a six-cylinder diesel that's a genuinely different design — smoother and more powerful than its four-cylinder stablemates.
We continue to rebuild and replace M256 engines for every GLC400D on the road.
MERCEDES GLC400D ENGINE CODES
M256 (R190, 2023–present)
A 3.0-litre inline-six petrol mild-hybrid engine fitted to the GLC400D 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 GLC400DMERCEDES GLC400D ENGINE COMPATIBILITY
The GLC400d uses the OM656 engine exclusively, which is specific to the X254 generation. Because this engine is a recent introduction, compatibility checks matter — particularly when sourcing replacement parts or considering a used unit from another model. Before we quote or supply anything, we 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 GLC-Class quote — it protects you from paying for parts that don't fit your actual car.
MERCEDES GLC400D APPLICATIONS BY GENERATION
Generation
Chassis
Years
Engine Code
Fuel
MERCEDES GLC400D ENGINES BY YEAR
From the R190's launch in 2023, the GLC400D 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.
The M256 has been fitted to every GLC400D 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 GLC400D MODEL YEAR:
Mercedes GLC400d
2022 Engine Rebuild
Mercedes GLC400d
2023 Engine Rebuild
Mercedes GLC400d
2024 Engine Rebuild
Mercedes GLC400d
2025 Engine Rebuild
Mercedes GLC400d
2026 Engine Rebuild
If your registration year isn't listed above, get in touch — we'll confirm availability directly against your reg.
MERCEDES GLC400D ENGINE COSTS
A Mercedes GLC400d engine rebuild starts from
£2,800
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.
12 MONTH
UNLIMITED-MILEAGE
WARRANTY
MERCEDES GLC400D ENGINE SIZES
• Mercedes GLC400d 3.0 Litre Engine (M256, I6)
MERCEDES GLC400D FUEL TYPES
• Mercedes GLC400d Petrol Mild Hybrid Engine Rebuilds
RELATED MERCEDES GLC-CLASS VARIANTS
Most Mercedes GLC-Class engine rebuilds are completed within 3-5 working days.
Nationwide recovery and collection available for all GLC-Class models.