The Mercedes-Benz M264 is the turbocharged four-cylinder gasoline engine that replaced the M274 in longitudinally mounted Mercedes models from 2018. It belongs to Mercedes' modular engine family developed alongside the M256 inline-six, and it is built in 1.5-liter and 2.0-liter displacements. Key features include an aluminum block, a DOHC 16-valve head with CAMTRONIC two-stage intake valve lift, gasoline direct injection, a twin-scroll turbocharger and, on many versions, a 48-volt belt-driven starter-generator marketed as EQ Boost. It powers the facelifted C-Class W205, the E-Class W213 and the facelifted GLC.
Buyers care about the M264 because it sits in some of the most popular late-model Mercedes on the used market, including the C 200, C 300, E 200, E 300 and GLC 300. It is more efficient than its predecessor, meets stricter emissions standards and adds mild-hybrid technology, but that extra complexity brings new failure points that older engines simply did not have.
Variant matters here more than ever. The 1.5-liter is almost always paired with the 48V system, while the 2.0-liter exists both with and without it depending on model and market. Knowing exactly which version you are looking at helps you anticipate parts costs, common faults and how much tuning headroom is realistically available.
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Base Specifications
| Spec | Detail |
|---|---|
| Type | Inline four-cylinder, turbocharged gasoline, longitudinal mounting |
| Displacement | 1,497 cc (1.5L) / 1,991 cc (2.0L) |
| Block | Aluminum |
| Head | Aluminum, 4 valves per cylinder |
| Valvetrain | DOHC, chain-driven, variable cam timing, CAMTRONIC two-stage intake valve lift |
| Injection | Gasoline direct injection |
| Aspiration | Twin-scroll turbocharger with intercooler |
| Electrification | 48V belt-driven starter-generator (EQ Boost) on many versions |
| Bore x Stroke | 80.4 x 73.7 mm (1.5L) / 83.0 x 92.0 mm (2.0L) |
| Firing Order | 1-3-4-2 |
| Production Years | 2018 – early 2020s |
1.5-Liter Versions (M264 E15 DEH LA)
The 1.5-liter M264 was introduced with the 2018 C-Class facelift and replaced the 1.6-liter and the lower-output 2.0-liter M274 engines. In the C 200 and E 200 it works with the 48V EQ Boost system, which can add up to around 14 hp and 118 lb-ft for short bursts and handles smooth engine restarts.
M264 E15 DEH LA — 156 hp / 184 lb-ft
| Model | Chassis | Years |
|---|---|---|
| C 180 | W205 / S205 / C205 (facelift) | 2018–2021 |
M264 E15 DEH LA — 184 hp / 207 lb-ft (with EQ Boost)
| Model | Chassis | Years |
|---|---|---|
| C 200 | W205 / S205 / C205 (facelift) | 2018–2021 |
| E 200 | W213 / S213 | 2018–2020 |
2.0-Liter Versions (M264 E20 DEH LA)
The 2.0-liter M264 shares its bore and stroke with the M274 2.0 but is a new design. It is the engine behind the facelifted C 300, the E 300 and the facelifted GLC 300. In North America it was rated at 255 hp. A higher-output 2.0-liter version with EQ Boost, at around 299 hp, was also offered in some markets in models such as the E 350.
M264 E20 DEH LA — 258 hp / 273 lb-ft
| Model | Chassis | Years |
|---|---|---|
| C 300 | W205 / S205 / C205 / A205 (facelift) | 2018–2021 |
| E 300 | W213 / S213 | 2018–2023 |
| GLC 300 | X253 / C253 (facelift) | 2019–2022 |
Exact outputs and the presence of EQ Boost on the 2.0-liter vary by model year and market, so always confirm the specification of the individual car with its VIN data card.
How to Check a Used M264-Powered Car's History
On an M264-powered car, the service history should show regular oil changes with an approved low-viscosity oil, software updates performed at the dealer, and any work on the 48V system, such as the belt-driven starter-generator, the 48V battery or the DC/DC converter. Warnings about the electrical system, a start-stop function that never activates or hesitation when pulling away can indicate 48V problems that are expensive to repair outside warranty.
Because many of these cars are still relatively young, check whether any remaining factory or extended warranty transfers to you, and verify that the mileage is consistent across service and inspection records. Lease returns and fleet cars are common, so confirm the car's accident history and ownership timeline before committing.
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Key Strengths
The M264 delivers excellent efficiency for its performance. The 1.5-liter C 200 offers similar real-world pace to the older 2.0-liter C 200 while using less fuel, and the 2.0-liter C 300 and E 300 provide strong, linear acceleration with economy that rivals many diesels in mixed driving. CAMTRONIC valve lift and the twin-scroll turbo give good low-end response.
The 48V EQ Boost system is a genuine benefit when it works properly. Engine restarts in stop-start traffic are almost imperceptible, the electric assist fills in the brief moment before the turbo spools, and the system allows the engine to coast with reduced load. The result is a more refined driving experience than most four-cylinder rivals offer.
The engine also benefits from modern, modular engineering shared with the M256 inline-six and the OM654 diesel. The timing chain design has so far proven more robust than in some earlier Mercedes four-cylinders, and the core engine has not shown widespread internal failures.
Known Reliability Issues
48V Belt-Driven Starter-Generator (EQ Boost) Faults
Symptom: Warning messages about the electrical system or the 48V network, stop-start not working, hesitation on pull-away, a no-start condition or the car entering a limp mode.
Cause: Faults can occur in the belt-driven starter-generator, the 48V battery, the DC/DC converter or related software. Some issues have been addressed with software updates, while others require component replacement.
Severity: Moderate to high. Parts are expensive and diagnosis requires proper Mercedes diagnostic equipment.
Typical Mileage: Can appear at any mileage, including relatively early in the car's life.
Note: Check that all available software updates have been applied. Out of warranty, replacing 48V components can cost from roughly $1,200 to well over $2,900 depending on the part.
Camshaft Solenoid Oil Leaks
Symptom: Oil visible around the camshaft solenoids at the front of the cylinder head, oil in the connectors, or electrical faults related to cam timing.
Cause: As on many Mercedes engines, the solenoid seals can let oil migrate into the connectors and wiring harness over time.
Severity: Moderate. The solenoids are inexpensive, but oil reaching the harness or control units can turn a small repair into a major one.
Typical Mileage: More likely as the car ages, typically from around 50,000 miles (80,000 km).
Note: Inspect the connectors whenever the engine cover is removed. Early replacement is cheap insurance.
Coolant Leaks and Thermostat Problems
Symptom: Low coolant warnings, slow warm-up, fluctuating temperature or a sweet smell after driving.
Cause: Plastic coolant pipes, connectors and the electronically controlled thermostat can leak or fail with heat cycles. The compact engine bay makes some leaks difficult to spot.
Severity: Moderate. Running low on coolant risks overheating and, in turn, head gasket or turbo damage.
Typical Mileage: Commonly from around 37,000–75,000 miles (60,000–120,000 km).
Note: Use only Mercedes-approved coolant, and investigate any repeated low-coolant warnings rather than simply topping up.
Carbon Buildup on Intake Valves
Symptom: Rough idle, hesitation and a gradual loss of responsiveness, especially on cars used mostly for short trips.
Cause: The M264 uses direct injection only, so crankcase vapors can deposit carbon on the back of the intake valves without fuel washing them clean.
Severity: Low to moderate. Deposits build slowly and are rarely damaging, but they affect smoothness and efficiency.
Typical Mileage: Usually noticeable beyond around 62,000 miles (100,000 km).
Note: Walnut blasting is the most effective cleaning method. Regular highway driving and on-time oil changes help.
Ignition Coils and Spark Plugs
Symptom: Misfires under load, rough running and misfire codes such as P0300–P0304.
Cause: High cylinder pressures in a small-displacement turbo engine put stress on spark plugs and coils, especially when plugs are overdue.
Severity: Low if dealt with promptly; prolonged misfiring can damage the catalytic converter and gasoline particulate filter where fitted.
Typical Mileage: Any mileage, but most often as plugs reach the end of their service life.
Note: Replace plugs on schedule and shorten the interval on tuned cars.
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) |
| Spark plugs | Per Mercedes service schedule, typically around 37,000 miles (60,000 km) (sooner if tuned) |
| Cabin filter | Every 12,500 miles (20,000 km) or 12–24 months |
| Brake fluid | Every 2 years |
| Coolant | Check at every service; replace per Mercedes schedule |
| 9G-TRONIC fluid and filter | Every 37,000–62,000 miles (60,000–100,000 km) (recommended) |
| Accessory belt (drives the 48V starter-generator) | Inspect at every service; replace when worn or per schedule |
| Software updates | Check for updates at every dealer visit |
Recommended oil specification: A fully synthetic oil approved to MB 229.71 (0W-20) or MB 229.5, as listed in the vehicle's service booklet for your specific model and market.
Tuning Potential
The M264 can be tuned, but it is a more complicated platform than the M274. Newer Mercedes engine control units are harder to access, and the 48V system, gasoline particulate filter (on later versions) and transmission software all need to be considered. The 2.0-liter offers the most worthwhile gains, while the 1.5-liter gains are smaller in absolute terms. The figures below are typical estimates and vary by tuner, fuel and market.
| Stage | Modifications | Estimated Power |
|---|---|---|
| Stage 1 (1.5L, 184 hp) | ECU remap or piggyback module | Around 205–220 hp |
| Stage 1 (2.0L, 258 hp) | ECU remap or piggyback module | Around 290–310 hp |
| Stage 2 (2.0L) | Remap, upgraded intercooler, intake, transmission calibration | Around 310–330 hp |
Recommended first modifications in priority order:
- Confirm all factory software updates and a healthy 48V system before tuning
- Fresh spark plugs and coil inspection
- Reputable ECU tune or piggyback module from a tuner experienced with the M264
- Upgraded intercooler for consistent performance in warm weather
- 9G-TRONIC transmission calibration to match the higher torque
Intake air temperature control and fuel quality are the key limits on a tuned M264, so use high-octane fuel and keep the cooling system in perfect order. Be aware that tuning may affect your warranty, and that removing the gasoline particulate filter or other emissions equipment is illegal for road use in the EU, the UK and the US.
FAQ
Is the Mercedes M264 a reliable engine?
Generally yes. The core engine has a good record so far, and most reported problems involve the 48V mild-hybrid system, cooling components or ancillaries rather than internal failures. Long-term data is still building because the engine is relatively young.
What are the most common M264 problems?
The most commonly reported issues are 48V EQ Boost system faults, camshaft solenoid oil leaks, coolant leaks or thermostat problems, carbon buildup on the intake valves and ignition-related misfires.
How long does an M264 engine last?
With proper maintenance, the M264 should be capable of 155,000 miles (250,000 km) or more. Regular oil changes with the correct specification and prompt attention to cooling system leaks are the most important factors.
How does the M264 compare to the M274?
The M264 is more efficient, cleaner and more refined thanks to CAMTRONIC, the twin-scroll turbo and the 48V system. The M274 is simpler, easier and cheaper to repair, and easier to tune. If you prefer fewer electrical components, the M274 is the more straightforward choice; if you want the latest refinement, the M264 is better. Its larger modular sibling is covered in our M256 engine guide.
How much power can an M264 make?
The 2.0-liter typically reaches around 290–330 hp with a tune and supporting modifications. Beyond that, the stock turbo and transmission become the limiting factors.
Is a tuned M264 still daily-drivable?
Yes, provided the tune is from a reputable source and the 48V system and transmission are correctly integrated. A mild Stage 1 keeps the car smooth and refined for daily use.
Conclusion
The Mercedes-Benz M264 is a refined and efficient four-cylinder that makes the facelifted C-Class, E-Class and GLC pleasant everyday cars. The core engine appears sound, but the 48V mild-hybrid system adds an expensive potential failure point, so a documented service history, up-to-date software and a careful inspection are essential. Buy the right car, maintain it properly, and the M264 should prove a dependable companion.
Overall Reliability Score: 7/10
Tuning Score: 6/10
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