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Mercedes M279 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The 6.0-litre twin-turbocharged V12 petrol engine fitted to flagship Mercedes-Benz and Maybach models from 2014 to 2020. Reconditioned Mercedes M279 units are typically available from £8,000 , reflecting the specialist nature of V12 biturbo replacement and consistent demand for this ultra-premium platform.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£4,000
Reconditioned from
£8,000
Rebuilt from
£12,000
GB
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Quotes only from vetted UK engine specialists.
Key Specs
Mercedes M279 - Specifications at a Glance
Engine Code
M279.980
Fuel
Petrol
Configuration
6.0L V12 twin-turbocharged (hot-vee layout)
Power Output(s)
390kW (530hp) - 463kW (630hp) depending on variant
Years Produced
2014-2020
UK Models Fitted
4+ Mercedes models - full list in Compatibility below
Replaced
M275
Replaced By
None (discontinued)
Most Common Failure
Timing chain stretch and turbocharger wastegate rattle
Reconditioned Price Range
£8,000-£14,000 supply-only
Vetted UK specialists for M279 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Mercedes Models Use the M279-
TAG: Fitted To
| Model | Generation/Chassis | Badge(s) | Years | Link |
|---|---|---|---|---|
 Mercedes-Benz S-Class | W222 | S 600, S 65 AMG | 2014-2020 | |
| Mercedes-Benz S-Class Coupe | C217 | S 600, S 65 AMG | 2014-2020 | |
| Mercedes-Benz Maybach | X222 | S 600, S 650 | 2015-2020 | |
| Mercedes-Benz G-Class | W463 | G 65 AMG | 2015-2018 |
02
Mercedes-Benz S-Class Coupe
03
Mercedes-Benz Maybach
04
Mercedes-Benz G-Class
CROSS-BRAND
M279 is documented across 4 BMW applications spanning S-Class, S-Class Coupe, Maybach, G-Class. Registration lookup confirms the exact suffix before quotes are sent.
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Prices
Mercedes M279 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £4,000-£8,000 | £5,170-£9,730 | 3-6 months |
Reconditioned | £8,000-£14,000 | £9,170-£15,730 | 12-24 months |
Rebuilt | £12,000-£18,000 | £13,170-£19,730 | 12-24 months |
The final cost of a Mercedes M279 engine replacement is heavily influenced by the condition of the twin turbochargers and the high-pressure fuel delivery system. If turbo failure has caused internal oil contamination or if the cylinder walls show signs of scoring, a standard reconditioned swap may not suffice, pushing the requirement toward a fully rebuilt unit with upgraded thermal management components. See our full reconditioned engine cost guide for a detailed breakdown of what is included at each price tier.
Labour Guide
Fitting a Mercedes M279 typically takes 18-26 hours at £65/hr (independent specialist rate) - confirm exact labour when comparing quotes, as the hot-vee turbo layout and extensive ancillary disassembly significantly increase labour time.
Price Factors
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Common Problems
Mercedes M279 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the M279, based on real-world data and verified failure patterns.
Verified issue focus: Timing chain stretch and turbocharger wastegate rattle.
1. Timing Chain Stretch and Guide Wear
1. Timing Chain Stretch and Guide Wear
Typical onset:
60,000-120,000 miles
What happens:
While improved over the M275, the M279 remains susceptible to timing chain stretch and plastic guide wear over time due to the extreme thermal loads of the hot-vee layout. This manifests as a distinct metallic rattling noise on cold starts, followed by check engine lights indicating camshaft correlation faults. If ignored, the chain can jump teeth, leading to catastrophic valve-to-piston contact.
Repair vs replace:
If caught early, replacing the timing chain kit, tensioners, and guides is viable, though it is a highly labour-intensive job requiring significant front-end strip-down. If internal damage has already occurred, a full Mercedes M279 engine replacement is the only reliable solution.
Read more about this issue
2. Turbocharger Wastegate Rattle and Bearing Wear
2. Turbocharger Wastegate Rattle and Bearing Wear
Typical onset:
70,000-120,000 miles
What happens:
The hot-vee layout places the twin turbochargers directly in the valley between the cylinder banks, subjecting them to extreme heat. This accelerates wastegate actuator wear and linkage rattle, leading to boost pressure faults and underboost complaints. In severe cases, bearing wear allows oil to leak into the intake or exhaust tract.
Repair vs replace:
Early wastegate rattle can sometimes be addressed with actuator replacement. However, if bearing wear has led to oil ingestion and internal engine scoring, the turbochargers must be replaced, which can push the requirement toward a fully rebuilt unit.
Read more about this issue
3. High-Pressure Fuel Pump (HPFP) and Injector Wear
3. High-Pressure Fuel Pump (HPFP) and Injector Wear
Typical onset:
80,000-120,000 miles
What happens:
The direct-injection system can suffer from HPFP wear or injector seal degradation over time. This leads to rough idle, misfires, extended cranking times, and in severe cases, fuel dilution of the engine oil, which compromises lubrication and accelerates bearing wear.
Repair vs replace:
Individual pump or injector replacement is the standard fix. However, if fuel dilution has gone unnoticed and caused crankshaft bearing wear, a full rebuild is necessary to prevent catastrophic bottom-end failure.
Read more about this issue
Compare rebuilt M279 prices with the failure already addressed
Engine Variants
How to Confirm You Have the Mercedes M279
The M279.980 engine code is stamped directly onto a machined pad on the engine block, typically located near the oil filter housing or the bell housing. It is also clearly listed on your vehicle's V5C registration document under "Engine Number" and can be decoded from the full VIN. Common Confusion Warning: Owners frequently confuse the M279 with other Mercedes flagship engines: - M275: The predecessor 5.5L/6.0L V12 biturbo. While mechanically similar, the M275 features different turbo plumbing, ECU mapping, and exhaust routing, making it incompatible as a direct swap. - M177: The newer 4.0L V8 biturbo. It features a completely different block architecture, hot-vee turbo sizing, and engine management system. - M278: The 4.6L/5.5L V8 biturbo. While sharing the hot-vee architecture, it differs significantly in displacement, cylinder count, and mounting. Fitting the wrong revision will result in severe ECU, wiring loom, and exhaust manifold incompatibilities.
Not 100% sure- Enter your registration above - we'll confirm your exact M279 fitment before any quotes are sent.
Easily Confused
M275
- The 5.5L/6.0L V12 biturbo it replaced; the M279 features twin-scroll turbos and direct injection, largely resolving the M275's early turbo actuator and thermal management weaknesses.
Alternative / Next-Gen Code
None (discontinued)
The V12 engine was discontinued after the 2020 model year in favor of electrified V8 and inline-6 powertrains across the flagship lineup.
Related JLR Variants
M177
- The 4.0L V8 biturbo counterpart of the same modular era; owners of V8-powered S-Class or G-Class models should look here, as the M177 shares the hot-vee architecture but differs significantly in displacement and mounting.
Confirm the exact M279 fitment
Not 100% sure- Enter your registration above - we'll confirm your exact M279 fitment before any quotes are sent.
Buying Guide
Buying a Replacement Mercedes M279 - What to Choose
Choosing the right replacement route depends on your budget, risk tolerance, and ownership goals. Here's a breakdown of your options.
Used:
A used Mercedes M279 is only advisable for lower-mileage host vehicles and *only* if accompanied by documented, stamped service history proving rigorous oil changes (every 5,000-8,000 miles) and no prior complaints of cold-start rattles or boost faults. The risk of inheriting timing chain stretch or turbo bearing wear is unacceptably high without this proof.
Reconditioned:
This is the most recommended route for the M279. A proper reconditioned unit will include brand-new timing chain components, tested twin turbochargers, refreshed valley pan seals, and new HPFP components, directly addressing the V12's known weak points out of the box.
Rebuilt:
A full rebuild is justified if your original M279 suffered catastrophic cylinder scoring that damaged the pistons, or if severe turbo failure caused oil starvation to the crankshaft bearings. A specialist rebuild will machine the block, fit upgraded thermal management components, and ensure all oil galleries are clear.
Supply & Fit Line:
Sourcing a replacement is only half the job. Our network provides full supply and fit services, ensuring the engine is installed by Mercedes and V12-specialist technicians with a nationwide warranty backing both the labour and the unit.
Vehicle Value Note:
For flagship hosts like the W222 S-Class, C217 Coupe, and X222 Maybach, current UK market values typically sit between £15,000 and £60,000 . With a reconditioned M279 replacement costing from £8,000 (plus £1,170-£1,730 fitting), the repair cost generally represents 20-40% of the vehicle's value, making replacement financially viable for well-maintained examples. However, for sub-£15,000 hosts, we strongly advise evaluating the car's scrap or part-exchange value before committing to a V12 engine replacement.
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Related Engines
Engines Related to the Mercedes M279
Explore engines that are closely related to the Mercedes-Benz M279, including its predecessor, successor, and key family variants.
Predecessor
M275
- The 5.5L/6.0L V12 biturbo it replaced; the M279 features twin-scroll turbos and direct injection, largely resolving the M275's early turbo actuator and thermal management weaknesses.
Successor
None (discontinued)
The V12 engine was discontinued after the 2020 model year in favor of electrified V8 and inline-6 powertrains across the flagship lineup.
Sibling
M177
- The 4.0L V8 biturbo counterpart of the same modular era; owners of V8-powered S-Class or G-Class models should look here, as the M177 shares the hot-vee architecture but differs significantly in displacement and mounting.
FAQ
Mercedes M279Frequently Asked Questions
Question 1How much does a Mercedes M279 engine replacement cost in the UK-
A Mercedes M279 engine replacement typically costs between £8,000 and £14,000 for a reconditioned supply-only unit . Fitted costs generally add £1,170-£1,730 for independent specialist labour due to V12 biturbo complexity, and fully rebuilt units with upgraded thermal management components can reach £12,000-£18,000 supply-only.
- Fitted costs generally add £1,170-£1,730 for independent specialist labour due to V12 biturbo complexity.
- Fully rebuilt units with upgraded thermal management components can reach £12,000-£18,000 supply-only.
Question 2What is the most common failure with the Mercedes M279 engine-
The most documented failure patterns for the M279 are timing chain stretch/guide wear and turbocharger wastegate rattle or bearing wear. Early warning signs include a metallic rattle on cold starts, camshaft correlation fault codes, or boost pressure faults, and if the chain jumps teeth or turbo bearing wear leads to oil ingestion, a full engine replacement is required to prevent catastrophic damage.
- Early warning signs include a metallic rattle on cold starts, camshaft correlation fault codes, or boost pressure faults.
- If the chain jumps teeth or turbo bearing wear leads to oil ingestion, a full engine replacement is required to prevent catastrophic damage.
Question 3Which Mercedes models use the M279.980 engine-
The M279.980 is fitted to flagship Mercedes-Benz all-wheel-drive sedans, coupes, and ultra-luxury derivatives from 2014 to 2020. This includes the S-Class (W222), S-Class Coupe (C217), Maybach (X222), and G-Class (W463), and you should always verify your exact fitment via registration lookup before ordering parts, as these are highly specialized applications.
- This includes the S-Class (W222), S-Class Coupe (C217), Maybach (X222), and G-Class (W463).
- You should always verify your exact fitment via registration lookup before ordering parts, as these are highly specialized applications.
Question 4Should I buy a used or reconditioned Mercedes M279 engine-
A reconditioned Mercedes M279 is strongly recommended over a used unit due to the well-documented timing chain and turbocharger failure risks. Used units carry a high probability of inheriting the same latent wear unless accompanied by stamped proof of preventative maintenance and no oil consumption complaints, whereas a proper reconditioned M279 includes verified cylinder bore integrity, new timing chain components, refreshed valley pan seals, and tested twin turbochargers as standard.
- Used units carry a high probability of inheriting the same latent wear unless accompanied by stamped proof of preventative maintenance and no oil consumption complaints.
- A proper reconditioned M279 includes verified cylinder bore integrity, new timing chain components, refreshed valley pan seals, and tested twin turbochargers as standard.
Question 5How do I know if my car has the M279 and not the M275 or M177-
The M279.980 engine code is stamped on the engine block near the oil filter housing and is listed on your V5C registration document. It is commonly confused with the older M275 or the newer V8 M177, but fitting an M275 or M177 will result in severe ECU, wiring loom, and exhaust manifold incompatibilities, making like-for-like replacement essential.
- It is commonly confused with the older M275 or the newer V8 M177.
- Fitting an M275 or M177 will result in severe ECU, wiring loom, and exhaust manifold incompatibilities, making like-for-like replacement essential.
Compare Mercedes M279 Engine Prices Today
Get a free, no-obligation comparison for your exact Mercedes M279 engine code. Our registration lookup confirms your precise fitment before any quotes are sent, ensuring you receive accurate pricing for your specific S-Class, Maybach, or G-Class. With reconditioned M279 units starting from an estimated £8,000, comparing specialist quotes takes just two minutes and could save you thousands on your replacement.
Vetted UK Specialists
Vetted UK specialists for M279 replacements
Minimum 12-Month Warranty
Minimum 12-month warranty on reconditioned and rebuilt options
Nationwide Delivery
Nationwide delivery plus supply and fit availability
Expert Support
Secure enquiry - no spam. Quotes only from vetted UK engine specialists.
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