The Mercedes-Benz M274 is the turbocharged four-cylinder gasoline engine that powered a huge share of rear-wheel-drive and 4MATIC Mercedes models during the 2010s. Introduced in 2012 as the longitudinal counterpart to the transverse M270 used in the compact cars, it combines an aluminum block, a DOHC 16-valve head, spray-guided direct injection and a single turbocharger in 1.6-liter and 2.0-liter displacements. You will find it under the hood of the C-Class W205, the late E-Class W212, the early E-Class W213, the GLC and the SLC roadster.
For used-car buyers, the M274 matters because it is everywhere. It replaced the older supercharged and turbocharged M271 four-cylinder and was itself succeeded by the M264 from 2018 onward, which means a large number of affordable C 200, C 300, E 200 and GLC 300 models on the market today run this engine. It is generally regarded as a solid, efficient unit, but it has a handful of well-documented weak points that are cheap to fix early and expensive to ignore.
Knowing which power output and which model year you are looking at is important. The same 2.0-liter hardware was sold at several outputs that differ mostly in software, so the parts you need, the tuning headroom and even some common faults depend on the exact variant. This guide breaks down the versions, the known problems, the maintenance schedule and what the M274 can realistically deliver with tuning.
Parts & Accessories
Your Mercedes deserves better.
Hand-picked performance and replacement parts — ready to ship.
Shop Mercedes parts →Specs & Versions
Base Specifications
| Spec | Detail |
|---|---|
| Type | Inline four-cylinder, turbocharged gasoline, longitudinal mounting |
| Displacement | 1,595 cc (1.6L) / 1,991 cc (2.0L) |
| Block | Aluminum |
| Head | Aluminum, 4 valves per cylinder |
| Valvetrain | DOHC, chain-driven, variable intake and exhaust cam timing |
| Injection | Spray-guided gasoline direct injection (BlueDIRECT) |
| Aspiration | Single turbocharger with intercooler |
| Bore x Stroke | 83.0 x 73.7 mm (1.6L) / 83.0 x 92.0 mm (2.0L) |
| Firing Order | 1-3-4-2 |
| Production Years | 2012 – around 2020 |
1.6-Liter Version (M274 DE16 AL)
The smaller 1.6-liter M274 shares the bore of the 2.0-liter but uses a shorter stroke. It was used mainly in entry-level C-Class models in markets where tax brackets favored smaller displacement.
M274 DE16 AL — 156 hp / 184 lb-ft
| Model | Chassis | Years |
|---|---|---|
| C 180 | W205 / S205 / C205 | 2014–2018 |
2.0-Liter Versions (M274 DE20 AL)
The 2.0-liter is the core of the range. The 184 hp, 211 hp and 245 hp outputs share the same basic hardware, with differences mainly in engine calibration, boost and supporting components. In the US market, the top output was rated at 241 hp.
M274 DE20 AL — 184 hp / 221 lb-ft
| Model | Chassis | Years |
|---|---|---|
| E 200 | W212 / S212 (facelift) | 2013–2016 |
| C 200 | W205 / S205 / C205 | 2014–2018 |
| E 200 | W213 | 2016–2018 |
| SLC 200 | R172 | 2016–2020 |
M274 DE20 AL — 211 hp / 258 lb-ft
| Model | Chassis | Years |
|---|---|---|
| E 250 | W212 / S212 (facelift) | 2013–2016 |
| C 250 | W205 / S205 | 2014–2018 |
| GLC 250 4MATIC | X253 | 2015–2019 |
M274 DE20 AL — 245 hp / 273 lb-ft
This is the most common version in North America, where it was badged C 300, E 300 and GLC 300 and rated at 241 hp with the same 273 lb-ft of torque.
| Model | Chassis | Years |
|---|---|---|
| C 300 | W205 / S205 / C205 | 2015–2018 |
| E 300 | W213 | 2016–2018 |
| GLC 300 | X253 | 2016–2019 |
| SLC 300 | R172 | 2016–2020 |
The 2.0-liter M274 was also paired with an electric motor in several plug-in hybrid models, and a version of it was supplied to Infiniti for the Q50 2.0t. Those applications have their own hybrid-specific considerations and are not covered in detail here.
How to Check a Used M274-Powered Car's History
With the M274, the service history tells you most of what you need to know. Look for oil changes at or below the factory interval with an MB 229.5-approved oil, evidence that the spark plugs were replaced on schedule, and any invoices mentioning camshaft adjusters, camshaft solenoids or timing chain work. A rattle for a second or two on a cold start, or oil found in the wiring harness near the front of the cylinder head, are signs to investigate before you buy.
Mileage verification matters too. Many M274-powered C-Class and E-Class cars were company or lease vehicles that covered high annual mileage, and a rolled-back odometer can hide a car that is due for timing chain or turbo work. Cross-check the mileage across service records, inspection reports and import documents, and confirm the car has no unresolved accident or flood history.
Get an instant 20% discount to access a vehicle's full past with total transparency via carVertical by clicking this link or on the banner below:
Key Strengths
The biggest strength of the M274 is its broad, accessible torque. Even the 184 hp version produces its peak torque from low engine speeds, so a C 200 or E 200 feels relaxed in everyday driving and pulls well when paired with the 7G-TRONIC or 9G-TRONIC automatic. The 245 hp version gives a C 300 genuinely brisk performance while still returning sensible fuel economy on the highway.
The engine is also well understood and well supported. Because it was fitted to hundreds of thousands of vehicles across several model lines, independent specialists know it well, diagnostic procedures are mature, and replacement parts such as ignition coils, spark plugs, camshaft solenoids, thermostats and gaskets are widely available at reasonable prices.
Finally, the M274 shows strong core durability when maintained properly. The bottom end is robust, catastrophic failures are rare, and most of the common faults are bolt-on components rather than internal engine damage. That makes it a sensible choice for buyers who want a modern turbocharged Mercedes without the complexity and running costs of a six-cylinder.
Known Reliability Issues
Camshaft Adjuster Rattle on Cold Start
Symptom: A short, loud rattle from the front of the engine for one to three seconds after a cold start, sometimes accompanied by a check engine light and camshaft position correlation codes such as P0016 or P0017.
Cause: The camshaft adjusters (phasers) can fail to lock correctly at startup, allowing them to rattle until oil pressure builds. In some cases the timing chain or its tensioner also shows wear.
Severity: Moderate. It does not usually cause immediate damage, but it should not be ignored because worn components can affect cam timing over time.
Typical Mileage: Often reported from around 37,000–75,000 miles (60,000–120,000 km), and sometimes earlier on cars with stretched oil change intervals.
Note: Repair usually involves replacing the adjusters and inspecting the chain, tensioner and guides at the same time. Expect roughly $900–2,100 at an independent specialist depending on what is replaced.
Camshaft Solenoid Oil Leaks
Symptom: Oil residue around the camshaft solenoids (magnets) on the front of the cylinder head, oil inside the connector plugs, and in worse cases oil wicking along the wiring harness toward the engine control unit.
Cause: The internal seals of the solenoids degrade with heat and age, allowing engine oil to travel through the connector and into the harness. This is a long-standing issue across several Mercedes engine families.
Severity: Moderate to high if left untreated, because oil reaching the ECU or harness can create electrical faults that are far more expensive to repair than the solenoids themselves.
Typical Mileage: Commonly from around 50,000 miles (80,000 km), though it can appear earlier.
Note: Replacing the solenoids is relatively inexpensive (often $150–450 for parts and labor). If oil is already in the harness, a harness section or adapter may also be needed. Check the connectors on any used car you inspect.
Turbo Wastegate Rattle
Symptom: A metallic rattle or buzzing from the turbo area, most noticeable on deceleration or at idle, sometimes with underboost codes.
Cause: Wear in the wastegate linkage or the wastegate flap bushing allows excessive play, which creates noise and can eventually affect boost control.
Severity: Low to moderate. Early on it is mostly an annoyance, but advanced wear can lead to boost control faults.
Typical Mileage: Often from around 50,000–93,000 miles (80,000–150,000 km).
Note: Depending on the cause, the fix ranges from replacing the actuator or linkage to replacing the turbocharger. A replacement turbo, including labor, typically costs $1,400–2,900.
Thermostat and Coolant Leaks
Symptom: Engine slow to reach operating temperature, temperature gauge fluctuating, low coolant warnings, or dried coolant residue around hoses and the thermostat housing.
Cause: The electronically controlled thermostat can fail open, and plastic coolant connectors and hoses can crack or leak with age and heat cycles.
Severity: Moderate. A failed thermostat hurts efficiency and triggers fault codes; a coolant leak left unchecked risks overheating.
Typical Mileage: Commonly from around 50,000–87,000 miles (80,000–140,000 km).
Note: Use only Mercedes-approved coolant when topping up or refilling. A thermostat replacement usually costs roughly $300–600.
Carbon Buildup on Intake Valves
Symptom: Rough idle, hesitation, gradual loss of performance and occasional misfire codes, especially on cars used mainly for short trips.
Cause: With direct injection, fuel never washes over the back of the intake valves, so oil vapor from the crankcase ventilation system bakes onto them over time.
Severity: Low to moderate. It develops slowly and is rarely damaging, but heavy deposits noticeably affect smoothness.
Typical Mileage: Usually becomes noticeable beyond around 62,000 miles (100,000 km).
Note: Walnut blasting the intake ports is the most effective cleaning method. Regular longer drives and timely oil changes help slow the process.
Ignition Coils and Spark Plugs
Symptom: Misfires under load, rough running and a flashing check engine light, often with cylinder-specific misfire codes (P0301–P0304).
Cause: Turbocharged direct-injection engines place high demands on spark plugs and coils. Overdue plugs increase the load on the coils and accelerate their failure.
Severity: Low if addressed promptly, but prolonged misfiring can damage the catalytic converter.
Typical Mileage: Any mileage, but most often when plugs are overdue.
Note: Replace plugs on schedule, and sooner on tuned cars. Coils are inexpensive and easy to swap.
Maintenance Schedule
| Service | Interval |
|---|---|
| Engine oil and filter | Every 6,000–9,500 miles (10,000–15,000 km) or 12 months (shorter than the maximum flexible interval is recommended) |
| Air filter | Every 25,000–37,000 miles (40,000–60,000 km), sooner in dusty conditions |
| Spark plugs | Every 37,000 miles (60,000 km) or per Mercedes service schedule (sooner if tuned) |
| Cabin filter | Every 12,500 miles (20,000 km) or 12–24 months |
| Brake fluid | Every 2 years |
| Coolant | Check annually; replace per Mercedes schedule or around every 5 years |
| Automatic transmission fluid and filter | Every 37,000–62,000 miles (60,000–100,000 km) (recommended even where not listed as mandatory) |
| Accessory drive belt and tensioner | Inspect at every service; replace around 62,000–75,000 miles (100,000–120,000 km) |
| Camshaft solenoid connectors | Inspect for oil at every service |
Recommended oil specification: A fully synthetic oil approved to MB 229.5 (commonly 0W-30, 5W-30 or 5W-40), or the specification listed in your vehicle's service booklet. Check the oil level regularly between services.
Tuning Potential
The 2.0-liter M274 responds well to software tuning because many versions share the same core hardware. A 184 hp or 211 hp engine can typically be lifted close to, or slightly beyond, the output of the factory 245 hp version with an ECU remap alone. The 245 hp version has less headroom left on stock hardware, but it still gains noticeably in midrange torque. The 1.6-liter version gains proportionally but has a lower ceiling. Figures below are typical estimates for the 2.0-liter and vary by tuner, fuel quality and transmission.
| Stage | Modifications | Estimated Power |
|---|---|---|
| Stage 1 (184/211 hp versions) | ECU remap only | Around 240–265 hp |
| Stage 1 (245 hp version) | ECU remap only | Around 280–295 hp |
| Stage 2 | Remap, upgraded intercooler, high-flow intake, downpipe (where legal) | Around 300–320 hp |
| Stage 3 | Hybrid or larger turbo, fueling upgrades, custom calibration | Around 340+ hp (high cost, reduced durability margin) |
Recommended first modifications in priority order:
- Fresh spark plugs (one step colder for higher boost) and healthy ignition coils
- Camshaft adjuster, solenoid and timing chain health check before adding power
- Quality ECU remap from an experienced Mercedes tuner
- Upgraded intercooler to control intake temperatures
- Transmission software adaptation to match the new torque curve
Keep in mind that the 7G-TRONIC and 9G-TRONIC automatics have torque limits, so aggressive tunes should include transmission calibration and conservative torque ramps. Heat is the main enemy of a tuned M274: an uprated intercooler, high-octane fuel and strict oil change intervals do more for longevity than chasing a peak power number. Exhaust modifications that remove or alter emissions equipment are not legal for road use in many countries.
FAQ
Is the Mercedes M274 a reliable engine?
Yes, overall. The M274 is considered a durable engine with a strong bottom end. Most problems involve components such as camshaft adjusters, camshaft solenoids, the thermostat and the turbo wastegate rather than internal engine failure. A well-maintained example is a sound purchase.
What are the most common M274 problems?
The most frequently reported issues are camshaft adjuster rattle on cold start, oil leaking through the camshaft solenoids into the wiring, turbo wastegate rattle, thermostat failure and carbon buildup on the intake valves.
How long does an M274 engine last?
With regular oil changes and timely repairs, many M274 engines comfortably exceed 155,000 miles (250,000 km). Neglected oil changes are the biggest threat to longevity because they accelerate wear on the timing components and turbocharger.
How does the M274 compare to the M271 and M270?
The M274 replaced the longitudinal M271 and is generally considered a step forward in efficiency and timing chain durability. It is closely related to the transverse M270 used in the A-Class, B-Class and CLA, and the two share many design features and some typical faults.
How much power can an M274 safely make?
On stock internals, around 280–320 hp is a common target for the 2.0-liter with supporting modifications. Going beyond that requires a larger turbo and fueling upgrades, and pushes the transmission and engine closer to their limits.
Is a tuned M274 still daily-drivable?
Yes. A quality Stage 1 tune keeps the car smooth and drivable while improving midrange response. Stick to reputable tuners, keep maintenance intervals short and monitor the car for misfires or unusual noises.
Conclusion
The Mercedes-Benz M274 is a dependable, efficient and well-supported turbocharged four-cylinder that suits everyday drivers and moderate enthusiasts alike. Its weak points are well known and mostly affordable to fix: camshaft adjusters, camshaft solenoids, the thermostat and the turbo wastegate. Choose a car with a documented service history, inspect it for the issues outlined above, and the M274 should provide many years of reliable service.
Overall Reliability Score: 7.5/10
Tuning Score: 7/10
Whether you are maintaining your C-Class, E-Class or GLC or preparing it for more power, browse our selection of Mercedes-Benz replacement and performance parts to keep your M274 running at its best.