01
Mercedes M274 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The 2.0-litre turbocharged longitudinal petrol engine fitted to core Mercedes-Benz models from 2012 to 2020, including the C-Class, E-Class, and GLC. Reconditioned Mercedes M274 units are typically available from £3,800 , reflecting consistent specialist demand for this widely used platform.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£2,000
Reconditioned from
£3,800
Rebuilt from
£5,500
GB
Secure enquiry - no spam.
Quotes only from vetted UK engine specialists.
Key Specs
Mercedes M274 - Specifications at a Glance
Engine Code
M274 (M274.920, M274.921)
Fuel
Petrol
Configuration
2.0L inline-4 turbocharged (longitudinal mounting)
Power Output(s)
135kW (184hp) to 180kW (245hp) depending on tune
Years Produced
2012-2020
UK Models Fitted
5+ Mercedes models - full list in Compatibility below
Replaced
M271 / M271.951/952
Replaced By
M264 / M254
Most Common Failure
Timing chain stretch and PCV diaphragm failure
Reconditioned Price Range
£3,800-£6,500 supply-only
Vetted UK specialists for M274 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Mercedes Models Use the M274-
TAG: Fitted To
| Model | Generation/Chassis | Badge(s) | Years | Link |
|---|---|---|---|---|
 Mercedes-Benz C-Class | W204 (Late) | C250 | 2012-2014 | |
| Mercedes-Benz C-Class | W205 | C200, C250, C300 | 2014-2021 | |
| Mercedes-Benz E-Class | W213 | E200, E250, E300 | 2016-2020 | |
| Mercedes-Benz GLC | X253 | GLC200, GLC250, GLC300 | 2015-2022 | |
| Mercedes-Benz S-Class | W222 | S300h (Hybrid ICE) | 2013-2020 |
02
Mercedes-Benz C-Class
03
Mercedes-Benz E-Class
04
Mercedes-Benz GLC
05
Mercedes-Benz S-Class
CROSS-BRAND
M274 is documented across 5 BMW applications spanning C-Class, E-Class, GLC, S-Class. Registration lookup confirms the exact suffix before quotes are sent.
Not sure which engine your car has?
Not sure which engine your car has- Enter your registration above - we'll confirm your exact M274 fitment before any quotes are sent.
Prices
Mercedes M274 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £2,000-£3,800 | £2,520-£4,580 | 3-6 months |
Reconditioned | £3,800-£6,500 | £4,320-£7,280 | 12-24 months |
Rebuilt | £5,500-£8,500 | £6,020-£9,280 | 12-24 months |
The final cost of a Mercedes M274 engine replacement is heavily influenced by the condition of the PCV system and the history of the timing chain. If the PCV diaphragm has ruptured and drawn oil into the intake tract, the intercooler and throttle body will require extensive cleaning or replacement alongside the engine swap. See our full reconditioned engine cost guide for a detailed breakdown of what is included at each price tier.
Labour Guide
Fitting a Mercedes M274 typically takes 8-12 hours at £65/hr (independent specialist rate) - confirm exact labour when comparing quotes.
Price Factors
Ready to compare M274 quotes?
Get competitive quotes from trusted UK specialists today.
Common Problems
Mercedes M274 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the M274, based on real-world data and verified failure patterns.
Verified issue focus: Timing chain stretch and PCV diaphragm failure.
1. Timing Chain Stretch and Tensioner Wear (Early Models)
1. Timing Chain Stretch and Tensioner Wear (Early Models)
Typical onset:
50,000-90,000 miles
What happens:
Early production M274 engines (roughly 2012-2015) inherited a timing chain tensioner vulnerability from the outgoing M271 family. The tensioner can fail to maintain adequate hydraulic pressure, leading to chain stretch, a distinct metallic rattle on cold starts, and camshaft correlation fault codes. If ignored, the chain can jump teeth, causing catastrophic valve-to-piston contact.
Repair vs replace:
If caught early, a full timing chain kit and updated tensioner replacement is viable. However, if the chain has already jumped and caused internal damage, a full Mercedes M274 engine replacement is the only reliable solution.
Read more about this issue
2. PCV Valve Diaphragm Failure and Oil Consumption
2. PCV Valve Diaphragm Failure and Oil Consumption
Typical onset:
60,000-100,000 miles
What happens:
The crankcase ventilation (PCV) valve diaphragm can rupture over time, leading to a distinct whining noise from the valve cover, increased oil consumption, and a rough idle. In severe cases, the ruptured diaphragm draws excess oil vapour into the intake tract, fouling the intercooler, throttle body, and intake valves.
Repair vs replace:
The PCV valve is integrated into the valve cover on the M274, meaning the entire valve cover must be replaced rather than just the diaphragm. This is a relatively straightforward repair and does not typically require engine replacement unless severe oil starvation has caused bottom-end bearing damage.
Read more about this issue
Compare rebuilt M274 prices with the failure already addressed
Engine Variants
How to Confirm You Have the Mercedes M274
The M274 engine code (including sub-codes M274.920 and M274.921) 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. The M274.920 typically denotes the 184hp tune (C200/E200/GLC200), while the M274.921 denotes the higher-output 211hp/245hp tune (C250/E250/GLC300). Common Confusion Warning: Owners frequently confuse the longitudinal M274 with several other Mercedes 2.0L and 1.8L engines: - M270: The M270 is the transverse-mounted version of this engine, fitted to front-wheel-drive compact models (A-Class, B-Class, CLA, GLA). Fitting an M270 into a longitudinal W205 or W213 will result in severe mounting, exhaust, and wiring incompatibilities. - M264: The M264 is the direct successor in the W205 facelift and W213, featuring a 48V mild-hybrid system (ISG) and different engine mount points. While both are 2.0L longitudinal turbos, they are not direct swap replacements without extensive ECU and wiring modifications. - M271: The older 1.8L turbo/supercharged engine. While it shares some architectural DNA, the M271 has different displacement, mounting, and engine management systems.
Not 100% sure- Enter your registration above - we'll confirm your exact M274 fitment before any quotes are sent.
Easily Confused
M271
/ - The 1.8L turbocharged predecessor it replaced, which featured older port-injection or early direct-injection setups and suffered from different timing chain tensioner vulnerabilities.
Alternative / Next-Gen Code
M264
- The direct 2.0L longitudinal successor introduced from 2017, which added a 48V mild-hybrid system (ISG) and revised engine mounts, making it physically incompatible as a direct swap despite the shared displacement.
Related JLR Variants
M270
- The transverse-mounted variant of this engine family, fitted to front-wheel-drive compact models like the A-Class and B-Class; owners of FWD platforms should check this page instead, as the M270 is not a direct physical swap.
Confirm the exact M274 fitment
Not 100% sure- Enter your registration above - we'll confirm your exact M274 fitment before any quotes are sent.
Buying Guide
Buying a Replacement Mercedes M274 - 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 M274 is only advisable for lower-mileage host vehicles and *only* if accompanied by documented, stamped service history proving the timing chain and tensioner have been replaced with updated components. Without this history, the risk of inheriting the same catastrophic stretch issues on early models is unacceptably high.
Reconditioned:
This is the most recommended route for the M274. A proper reconditioned unit will include a brand-new timing chain kit, an updated tensioner, and a new valve cover with a fresh PCV diaphragm, directly addressing the engine's known weak points out of the box.
Rebuilt:
A full rebuild is justified if your original M274 suffered a jumped timing chain that damaged the cylinder head, valves, or pistons, or if severe PCV failure caused oil starvation to the crankshaft bearings. A specialist rebuild will machine the block, fit updated timing 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-specialist technicians with a nationwide warranty backing both the labour and the unit.
Vehicle Value Note:
For core hosts like the W205 C-Class and X253 GLC, current UK market values typically sit between £8,000 and £25,000 . With a reconditioned M274 replacement costing from £3,800 (plus fitting), the repair cost generally represents 20-40% of the vehicle's value, making replacement financially viable. However, for early W204 C250 hosts valued under £5,000, we strongly advise evaluating the car's scrap or part-exchange value before committing to a full engine replacement.
Compare M274 Engine Prices Now
Related Engines
Engines Related to the Mercedes M274
Explore engines that are closely related to the Mercedes-Benz M274, including its predecessor, successor, and key family variants.
Predecessor
M271
/ - The 1.8L turbocharged predecessor it replaced, which featured older port-injection or early direct-injection setups and suffered from different timing chain tensioner vulnerabilities.
Successor
M264
- The direct 2.0L longitudinal successor introduced from 2017, which added a 48V mild-hybrid system (ISG) and revised engine mounts, making it physically incompatible as a direct swap despite the shared displacement.
Sibling
M270
- The transverse-mounted variant of this engine family, fitted to front-wheel-drive compact models like the A-Class and B-Class; owners of FWD platforms should check this page instead, as the M270 is not a direct physical swap.
FAQ
Mercedes M274Frequently Asked Questions
Question 1How much does a Mercedes M274 engine replacement cost in the UK-
A Mercedes M274 engine replacement typically costs between £3,800 and £6,500 for a reconditioned supply-only unit . Fitted costs generally add £520-£780 for independent specialist labour, and fully rebuilt units with upgraded components can reach £5,500-£8,500 supply-only.
- Fitted costs generally add £520-£780 for independent specialist labour.
- Fully rebuilt units with upgraded components can reach £5,500-£8,500 supply-only.
Question 2What is the most common failure with the Mercedes M274 engine-
The most documented failure pattern for the M274 is timing chain stretch and tensioner wear on early production models (2012-2015), typically occurring between 50,000 and 90,000 miles. Early warning signs include a metallic rattle on cold starts and camshaft correlation fault codes, and additionally, PCV valve diaphragm failure is common, leading to oil consumption and intake tract contamination.
- Early warning signs include a metallic rattle on cold starts and camshaft correlation fault codes.
- Additionally, PCV valve diaphragm failure is common, leading to oil consumption and intake tract contamination.
Question 3Which Mercedes models use the M274 engine-
The M274 is fitted to Mercedes-Benz longitudinal rear-wheel-drive and 4MATIC models from 2012 to 2020, including the C-Class (W204 late/W205), E-Class (W213), GLC (X253), and S-Class (W222 hybrid). It powers badges ranging from the C200 and C250 to the E300 and GLC300, and you should always verify your exact fitment via registration lookup before ordering parts.
- It powers badges ranging from the C200 and C250 to the E300 and GLC300.
- You should always verify your exact fitment via registration lookup before ordering parts.
Question 4Should I buy a used or reconditioned Mercedes M274 engine-
A reconditioned Mercedes M274 is strongly recommended over a used unit due to the well-documented timing chain tensioner and PCV diaphragm failure risks. Used units carry a high probability of inheriting the same latent wear unless accompanied by stamped proof of a full chain kit replacement, whereas a proper reconditioned M274 includes a new timing chain, updated tensioner, and a fresh PCV valve cover as standard.
- Used units carry a high probability of inheriting the same latent wear unless accompanied by stamped proof of a full chain kit replacement.
- A proper reconditioned M274 includes a new timing chain, updated tensioner, and a fresh PCV valve cover as standard.
Question 5How do I know if my car has the M274 and not the M270 or M264-
The M274 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 transverse M270 (FWD models) or the newer M264 (48V mild-hybrid models), but fitting an M270 or M264 will result in severe mounting, exhaust, and wiring loom incompatibilities, making like-for-like replacement essential.
- It is commonly confused with the transverse M270 (FWD models) or the newer M264 (48V mild-hybrid models).
- Fitting an M270 or M264 will result in severe mounting, exhaust, and wiring loom incompatibilities, making like-for-like replacement essential.
Compare Mercedes M274 Engine Prices Today
Get a free, no-obligation comparison for your exact Mercedes M274 engine code. Our registration lookup confirms your precise fitment before any quotes are sent, ensuring you receive accurate pricing for your specific vehicle. With reconditioned M274 units starting from an estimated £3,800, comparing specialist quotes takes just two minutes and could save you hundreds on your replacement.
Vetted UK Specialists
Vetted UK specialists for M274 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.
Secure enquiry - no spam. Quotes only from vetted UK engine specialists.
Get Free M274 Engine Quotes