Mercedes-Benz M274 Specifications
| Engine Model: Mercedes-Benz M274 |
| Engine Type: 4-cycle 4-cylinder DOHC 16-valve turbocharged liquid-cooled gasoline |
| Total Displacement: 97.3-121.5 cu.in (1.59-1.99 L) |
| Rated Engine Power: 127-241 Hp (95-180 kW) at 5500 rpm |
| Fuel System Type: BlueDIRECT injection |
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The Mercedes-Benz M274 is a turbocharged inline-four
gasoline engine introduced in 2012 as the longitudinal counterpart to the
transverse M270. Designed for rear-wheel-drive (RWD) and 4MATIC all-wheel-drive
configurations, the M274 was developed to meet the demands for reduced fuel
consumption, lower emissions, and responsive power delivery across the compact
and mid-range Mercedes-Benz passenger car lineup.
The engine family succeeded the naturally aspirated M271 and M272 powerplants,
incorporating a suite of advanced technologies to achieve a balance of
efficiency and low-end torque that became a hallmark of the Mercedes-Benz
four-cylinder range during the 2010s.
The M274 is available in two displacement variants: a 1.6-liter unit and a
2.0-liter unit, both utilizing a die-cast aluminum block with a closed-deck
design to withstand the elevated combustion pressures associated with
turbocharging. The engine employs a DOHC valvetrain with four valves per
cylinder and incorporates BlueDIRECT direct injection, which utilizes
third-generation piezoelectric injectors for precise fuel metering.
CAMTRONIC variable valve lift on the intake side, an electronically controlled
water pump, and a demand-controlled oil pump further contribute to thermal
efficiency and reduced parasitic losses. The M274 was manufactured in
Mercedes-Benz’s Unterturkheim plant and subsequently powered a wide range of
models, from the C-Class and E-Class to the GLC and SLC, with applications
extending to Infiniti under a technology-sharing agreement.
The M274 is a water-cooled, four-stroke, turbocharged gasoline engine configured
for longitudinal mounting in rear-wheel-drive and all-wheel-drive vehicle
architectures. The engine family encompasses two primary displacement variants
sharing identical bore dimensions.
Engine Type: Inline-4, 4-cycle, water-cooled, turbocharged.
Firing Order: 1-3-4-2.
Idle Speed: 700 ± 50 rpm.
Engine Redline: 6,300 rpm.
Valvetrain: DOHC, 16-valve (4 valves per cylinder) with chain drive and
CAMTRONIC variable valve lift (intake side).
1.6-Liter Variant (M274 DE 16 AL)
Displacement: 1,595 cc (97.3 cu.in).
Bore and Stroke: 83.0 mm (3.27 in) x 73.7 mm (2.90 in).
Compression Ratio: 10.3:1.
Maximum Power: 95-115 kW (127-154 Hp) at 5,000-5,500 rpm.
Maximum Torque: 210-250 Nm (155-184 lb-ft) at 1,250-4,000 rpm.
2.0-Liter Variant (M274 DE 20 AL)
Displacement: 1,991 cc (121.5 cu.in).
Bore and Stroke: 83.0 mm (3.27 in) x 92.0 mm (3.62 in).
Compression Ratio: 9.8:1.
Maximum Power (Standard): 135-155 kW (181-208 Hp) at 5,500 rpm.
Maximum Torque (Standard): 300-350 Nm (221-258 lb-ft) at 1,200-4,000 rpm.
Maximum Power (High Output): 180 kW (241 Hp) at 5,500 rpm.
Maximum Torque (High Output): 370 Nm (273 lb-ft) at 1,300-4,500 rpm.
The cylinder block is manufactured from die-cast
aluminum alloy, a selection that reduces overall engine mass and improves
thermal management compared to cast iron alternatives. The block utilizes a
closed-deck design, where the cylinder bores are fully supported by the water
jacket structure at the top deck surface, providing robust clamping force for
the cylinder head gasket and minimizing bore distortion under the elevated
cylinder pressures generated by turbocharging.
The cylinder bore surfaces are treated using twin-wire arc spraying (TWAS), a
process in which a thin layer of iron-carbon alloy is sprayed onto the aluminum
bore surface to create a high-wear-resistance coating. This technology
eliminates the need for cast iron cylinder liners, reduces friction between the
piston rings and cylinder wall, and improves heat transfer. The block
incorporates five main bearing webs with two-bolt main bearing caps.
The crankshaft is supported by five bearings and is constructed from forged
steel to withstand the torque outputs of both the 1.6-liter and 2.0-liter
variants. A plastic structural oil pan is sealed to the lower crankcase,
contributing to weight reduction while serving as the oil reservoir.
Block Material: Die-cast aluminum alloy
Bore Diameter (finished): 83.0 mm (3.27 in)
Cylinder Bore Coating: Twin-wire arc sprayed (TWAS) iron-carbon coating
Main Bearing Caps: Cast iron, two-bolt design
Cylinder Bore Deformation Limit: 0.03 mm (0.0012 in)
The cylinder head is manufactured from aluminum alloy
and incorporates a cross-flow design with the intake manifold on the rear side
and the exhaust manifold integrated into the cylinder head casting. This
integrated exhaust manifold reduces warm-up time by allowing coolant to
circulate through the head and rapidly bring the catalytic converter to
operating temperature.
The DOHC valvetrain actuates sixteen valves - two intake and two exhaust per
cylinder - through a system of roller rocker arms and hydraulic lash adjusters.
The intake camshaft incorporates CAMTRONIC variable valve lift, a two-stage
system that switches between a low-lift, short-duration profile for
fuel-efficient part-load operation and a high-lift, long-duration profile for
maximum power output.
The exhaust camshaft is equipped with continuously variable valve timing. Both
camshafts are driven by a roller chain from the crankshaft, with an automatic
hydraulic tensioner maintaining chain tension. The camshafts are hollow to
reduce rotational inertia and overall engine mass. The engine is of interference
design; precise timing chain integrity is required to prevent valve-to-piston
contact.
Head Material: Aluminum alloy.
Valve Configuration: DOHC, 4 valves per cylinder with roller rocker arms.
Valve Diameter (Intake): 33.5 mm (1.32 in).
Valve Diameter (Exhaust): 29.0 mm (1.14 in).
Valve Stem Diameter: 5.0 mm (0.20 in).
Valve Seat Angle: 45 degrees.
The M274 employs the BlueDIRECT third-generation direct
injection system. This system utilizes piezoelectric injectors mounted centrally
in the cylinder head, positioned to deliver fuel directly into the combustion
chamber at pressures up to 20.0 MPa (2,900 psi). The piezoelectric injectors
enable multiple injection events per combustion cycle - including up to five
separate injections - allowing for precise control of mixture formation, reduced
particulate emissions, and quieter combustion.
A high-pressure fuel pump, driven by a cam lobe on the intake camshaft, draws
fuel from the tank and delivers it to a stainless steel fuel rail that
distributes pressurized fuel to all four injectors. The engine control unit
(ECU) calculates injection parameters based on inputs from the mass airflow
sensor, throttle position sensor, coolant temperature sensor, crankshaft
position sensor, and a wideband oxygen sensor for precise air-fuel ratio control
across all operating conditions. Multi-spark ignition, in which the ignition
coil discharges multiple times per combustion cycle, complements the direct
injection system by improving combustion stability under lean operating
conditions.
Injection Type: BlueDIRECT direct injection (third-generation).
Injection Pressure: 20.0 MPa (2,900 psi) maximum.
High-Pressure Pump Type: Single-piston plunger pump, camshaft-driven.
Injector Type: Piezoelectric, centrally mounted.
Fuel Requirement: 91 octane (Research Octane Number 95) minimum for 2.0-liter
variants; 87 octane (Research Octane Number 91) minimum for 1.6-liter variants.
Fuel Cutoff: 6,500 rpm.
The lubrication system is a fully pressurized, wet-sump
design utilizing a variable-displacement vane-type oil pump mounted to the front
of the crankshaft. The oil pump adjusts its output based on engine speed and
load to reduce parasitic losses and improve fuel efficiency. The pump draws
lubricant from the plastic structural oil pan through a mesh strainer and
circulates it through a full-flow, replaceable oil filter before entering the
main oil gallery.
A pressure relief valve maintains system pressure within operational limits.
Piston cooling oil jets are incorporated to direct a stream of oil toward the
underside of each piston crown, managing thermal loads associated with
turbocharging. The lubrication system is designed to accommodate extended oil
change intervals while maintaining protection under the elevated combustion
pressures of the turbocharged architecture.
Oil Type: Synthetic, SAE 0W-40, 5W-40, or 5W-30.
Oil Capacity (with filter): 6.0-6.5 liters (6.3-6.9 US qt).
Oil Pressure (at 3,000 rpm): 300-400 kPa (43.5-58.0 psi).
Oil Pump Type: Variable-displacement vane-type, crankshaft-driven.
Oil Filter Type: Cartridge-type, replaceable element.
The cooling system is a pressurized, liquid-cooled
design employing a cross-flow aluminum radiator with an electric cooling fan. An
electronically controlled centrifugal-type water pump, driven by the timing
chain, circulates coolant through the engine block, cylinder head, integrated
exhaust manifold, turbocharger center housing, and heater core. The electronic
water pump operates independently of engine speed, allowing for
demand-controlled coolant flow that reduces warm-up time and improves fuel
efficiency.
A wax-pellet thermostat regulates coolant flow to maintain optimal operating
temperature, with an electronically controlled bypass valve that can override
the thermostat to accelerate warm-up or provide additional cooling under
high-load conditions. The system is designed to manage the thermal load
generated by the turbocharger and the integrated exhaust manifold.
Coolant Type: Ethylene-glycol based antifreeze with corrosion inhibitors.
Coolant Capacity: 7.5-8.5 liters (7.9-9.0 US qt) (variant dependent).
Thermostat Opening Temperature: 85-90 °C (185-194 °F).
Radiator Cap Pressure: 140-150 kPa (20.3-21.8 psi).
Water Pump Type: Centrifugal, electronically controlled, timing chain-driven.
| Intake and Exhaust Systems |
Intake System: Composite plastic intake manifold with
integrated charge air cooler and throttle body. The intake system incorporates
an air cleaner housing with a dry-type paper filter element. An electronically
controlled throttle body manages airflow into the engine.
Exhaust System: Cast stainless steel exhaust manifold integrated into the
cylinder head, with a single-entry flange mounting the turbocharger directly.
The system incorporates a heated oxygen sensor upstream of the turbocharger and
a downstream sensor after the catalytic converter for fuel trim feedback. The
close-coupled catalytic converter is positioned immediately after the
turbocharger to minimize light-off time.
Multi-spark ignition system with individual pencil-type
ignition coils mounted directly over each spark plug. The system delivers
multiple ignition events per combustion cycle at low and medium engine speeds to
improve combustion stability and reduce emissions. The ECU utilizes input from
the knock sensor, crankshaft position sensor, and camshaft position sensors to
adjust ignition timing per cylinder.
The M274 utilizes a single-scroll turbocharger mounted
to the integrated exhaust manifold. The turbocharger incorporates a water-cooled
bearing housing to prevent oil coking after engine shutdown. Boost pressure is
regulated by an electronically controlled wastegate actuator. Maximum boost
pressure varies by variant, ranging from 0.8 bar (11.6 psi) on lower-output
versions to 1.2 bar (17.4 psi) on high-output versions. An air-to-air
intercooler reduces intake air temperature before entering the engine.
Overall Length: 640 mm (25.2 in)
Overall Width: 640 mm (25.2 in)
Overall Height: 710 mm (28.0 in)
Dry Weight (complete engine): 139 kg (306 lb)
Oil Change Interval: Variable, up to 20,000 km (12,500
mi) or 1 year under normal driving conditions; reduced under severe conditions.
Oil Filter Change: At every oil change. Engine Coolant Replacement: 150,000 km
(93,000 mi) or 10 years; thereafter 60,000 km (37,500 mi) or 5 years. Drive Belt
(Accessory) Inspection: Every 20,000 km (12,500 mi) for tension, cracking, and
glazing.
Spark Plug Replacement: 60,000 km (37,500 mi) for 2.0-liter variants; 80,000 km
(50,000 mi) for 1.6-liter variants. Spark Plug Type: NGK SILZKFR8C7S or
equivalent (iridium-tipped). Spark Plug Gap: 0.7-0.8 mm (0.028-0.031 in). Air
Filter Replacement: 40,000 km (25,000 mi) or as indicated by inspection. Fuel
Filter: Integrated with fuel pump assembly; no scheduled replacement under
normal operating conditions.
Cylinder Head Bolts (M10 x 1.25), 1st pass: 40 Nm (30
lb-ft).
Cylinder Head Bolts (M10 x 1.25), 2nd pass: 80 Nm (59 lb-ft).
Main Bearing Cap Bolts (M8 x 1.25): 20 Nm (15 lb-ft).
Connecting Rod Cap Bolts (M8 x 1.0): 20 Nm (15 lb-ft).
Camshaft Bearing Cap Bolts (M8 x 1.25): 18-22 Nm (13-16 lb-ft).
Intake Manifold Bolts (M8 x 1.25): 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts (M8 x 1.25): 25-30 Nm (18-22 lb-ft).
Turbocharger Mounting Nuts (M8 x 1.25): 28-32 Nm (21-24 lb-ft).
Spark Plugs: 18-22 Nm (13-16 lb-ft).
Oil Pan Bolts (M6 x 1.0): 9-11 Nm (80-97 lb-in).
Water Pump Bolts (M8 x 1.25): 18-22 Nm (13-16 lb-ft).
Timing Chain Tensioner (M14 x 1.5): 40-45 Nm (30-33 lb-ft).
Crankshaft Pulley Bolt (M16 x 1.5): 1st pass: 150 Nm (111 lb-ft).
Flywheel / Drive Plate Bolts (M10 x 1.25): 70-75 Nm (52-55 lb-ft).
The Mercedes-Benz M274 engine was utilized across a
wide range of Mercedes-Benz passenger vehicle models, as well as in select
applications under the Infiniti brand through a technology-sharing agreement.
C-Class (W205): C 160, C 180, C 200, C 250, C 300 (2014-2021).
E-Class (W212, W213): E 180, E 200, E 250, E 300 (2013-2020).
GLC-Class (X253): GLC 200, GLC 250, GLC 300 (2015-2021).
SLC-Class (R172): SLC 200, SLC 300 (2016-2020).
CLS-Class (C218): CLS 260, CLS 300 (selected markets).
Infiniti Q50: 2.0t variant (2016-2020).
Infiniti Q60: 2.0t variant (2016-2020).
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