Chevrolet LKW Specifications
| Engine Model: Chevrolet LKW |
| Engine Type: 4-cycle 4-cylinder DOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 150 cu.in (2.45 L) |
| Rated Engine Power: 197 Hp (146 kW) at 6300 rpm |
| Fuel System Type: Spark Ignition Direct Injection (SIDI) |
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The Chevrolet LKW is a 2.5-liter naturally aspirated
inline-four gasoline engine, a specialized variant within General Motors’ Ecotec
Gen III family. Introduced for the 2014 model year, it served as the base
powerplant for several of GM’s large mid-size and full-size sedans. While
sharing its fundamental architecture with the LCV engine, the LKW is
distinguished by a unique valvetrain strategy. Its defining characteristic is
the implementation of Intake Valve Lift Control (IVLC), a system designed to
optimize fuel economy without compromising low-end responsiveness.
The engine was engineered for refinement, incorporating balance shafts and a
variable-displacement oil pump to deliver a smooth, quiet operation
characteristic of a larger-displacement unit. It represented a significant step
in GM’s strategy to improve fleet fuel efficiency through advanced valvetrain
technology and standard stop/start systems in the mainstream sedan market.
Engine Type: Inline 4-cylinder, 4-stroke, gasoline, Ecotec Gen III
Displacement: 2.5 L; 150 cu.in (2,457 cc)
Bore x Stroke: 88.0 mm x 100.8 mm (3.46 in x 3.97 in)
Compression Ratio: 11.3:1
Firing Order: 1-3-4-2
Horsepower: 196-197 hp @ 6,300 rpm
Torque: 186-191 lb-ft @ 4,400 rpm
Maximum Engine Speed: 7,000 rpm (fuel cut-off)
Material: Cast aluminum alloy with cast-in-place gray
cast-iron cylinder liners. The use of aluminum reduces overall engine mass,
while the iron liners provide a durable, low-friction surface for the piston
rings.
Design: An open-deck design is utilized, where the cylinders are not fully
enclosed by the upper deck of the block. This configuration enhances cooling
flow around the cylinder bores.
Structural Features: The block is designed with a deep-skirt configuration,
where the side walls extend below the crankshaft centerline. This increases
structural rigidity, minimizing noise, vibration, and harshness (NVH).
Balance Shafts: The block is machined to accommodate a balance shaft module
mounted within the oil pan. This module contains twin, counter-rotating shafts
that cancel out the inherent second-order vibrations of an inline-four engine.
Material: Cast aluminum alloy. Valvetrain: Dual
Overhead Camshaft (DOHC) with 4 valves per cylinder (16 total). The camshafts
are driven by a silent-type chain from the crankshaft. Valve Configuration:
Intake valves are inclined and exhaust valves are positioned to create a
compact, efficient pent-roof combustion chamber.
Intake Valve Lift Control (IVLC): This is the distinguishing feature of the LKW.
The system employs a unique rocker arm assembly on the intake side. Each intake
valve is actuated by two distinct rocker arms - one for low-lift and one for
high-lift - which are latched together via a solenoid-actuated locking pin. In
low-lift mode, the rocker arm follows a smaller cam lobe profile, reducing valve
lift and duration to promote tumble and swirl in the combustion chamber for
improved fuel efficiency. In high-lift mode, the pin locks the arms, allowing
the system to follow a larger cam lobe for increased airflow and power output.
This switch occurs seamlessly based on engine load and speed.
Exhaust Manifold: The exhaust manifold is integrated directly into the cylinder
head. This design reduces weight, simplifies packaging, and brings the catalytic
converter closer to the exhaust ports for faster light-off, reducing cold-start
emissions.
System Type: Spark Ignition Direct Injection (SIDI).
Fuel Requirement: Premium grade fuel is not required; the engine is calibrated
to operate on regular unleaded fuel with a minimum octane rating of 87 (R+M)/2.
Fuel Pressure: High-pressure direct injection system operating at pressures up
to 2,175 psi (15,000 kPa). A cam-driven high-pressure fuel pump mounted on the
cylinder head supplies fuel to the injectors.
Injectors: Solenoid-actuated direct injectors are centrally located between the
valves. This positioning directs the fuel spray precisely into the combustion
chamber, promoting a homogeneous air-fuel mixture for efficient combustion.
System Type: Pressurized, full-flow filtration system.
Oil Capacity: Approximately 5.7 L (6.0 qt) including the oil filter. Oil Pan:
Structural aluminum oil pan that houses the twin balance shafts and serves as a
mounting point for the oil pump.
Oil Pump: A two-stage, variable-displacement vane-type oil pump. The pump’s
output is adjusted by an electronic solenoid based on engine speed, load, and
temperature. At low loads, the pump operates in a low-pressure mode to reduce
parasitic drag on the engine, contributing to fuel economy. Under high load, it
switches to high-pressure mode to ensure adequate lubrication for critical
components.
Oil Specification: Requires dexos1-approved synthetic blend or full synthetic
engine oil. This specification ensures proper performance with the variable
valve timing and stop/start systems.
System Type: Liquid-cooled, pressurized, with a
cross-flow radiator configuration. Coolant: Specified to use GM DEX-COOL
extended-life coolant, which is an organic acid technology (OAT) formulation.
Water Pump: A belt-driven, centrifugal-type water pump mounted to the front of
the engine block. The system is designed for reverse cooling flow, directing
coolant to the cylinder head first to manage combustion chamber temperatures and
reduce the propensity for knock.
Thermostat: An electronically controlled thermostat that allows the Engine
Control Module (ECM) to actively manage coolant temperature. By maintaining
higher coolant temperatures at low loads, the system reduces internal friction.
At higher loads, the thermostat opens earlier to increase cooling capacity.
Features a composite plastic intake manifold designed
for reduced weight and improved air flow. The manifold incorporates an
integrated charge motion control valve (CMCV) system to enhance air-fuel mixing
at low engine speeds.
| Ignition and Starting System |
Ignition System: Individual coil-on-plug (COP) ignition
modules for each cylinder, eliminating spark plug wires for increased
reliability and precise ignition timing control.
Starting System: The LKW was among the first GM engines standardized with an
advanced stop/start system. This system utilizes a tandem-solenoid starter and
an auxiliary battery (in addition to the primary 12V battery) to enable seamless
engine shut-off during idle conditions. The starter is engineered for the
increased number of start cycles required by this system.
Overall Length: 645 mm (25.4 in)
Overall Width: 641 mm (25.2 in)
Overall Height: 660 mm (26.0 in)
Dry Weight: 124 kg (273 lb)
Oil Change Interval: Under normal driving conditions,
the Oil Life Monitoring System (OLMS) will indicate the need for an oil change,
typically between 7,500-10,000 miles (12,000-16,000 km). Severe service
intervals are reduced.
Engine Oil Capacity with Filter: 5.7 L (6.0 qt).
Engine Oil Viscosity: SAE 5W-30 meeting dexos1 Gen 2 or later specification.
Coolant Capacity (Engine Only): Approximately 4.5 L (4.8 qt).
Spark Plug Type: Iridium-tipped, pre-gapped.
Spark Plug Gap: 0.90-1.00 mm (0.035-0.039 in).
Spark Plug Replacement Interval: 97,000 km (60,000 miles).
Drive Belt: Serpentine belt with an automatic tensioner; inspection recommended
at regular intervals, with replacement typically required after 150,000 km
(90,000 miles). Air Filter: Replace as indicated by the Engine Air Filter Life
System, generally every 72,000 km (45,000 miles) under normal conditions.
Cylinder Head Bolts (Stage 1): 30 Nm (22 lb-ft)
Cylinder Head Bolts (Stage 2): 90-degree turn
Cylinder Head Bolts (Stage 3): Additional 80-degree turn
Main Bearing Cap Bolts: 50 Nm (37 lb-ft) + 90-degree turn
Connecting Rod Cap Nuts: 20 Nm (15 lb-ft) + 125-degree turn
Camshaft Bearing Cap Bolts: 12 Nm (106 lb-in)
Intake Manifold Bolts: 12 Nm (106 lb-in)
Exhaust Manifold Fasteners (to head): 20 Nm (15 lb-ft)
Spark Plugs: 15 Nm (11 lb-ft)
Oil Pan Bolts (M6): 12 Nm (106 lb-in)
Oil Pan Bolts (M8): 25 Nm (18 lb-ft)
Crankshaft Balancer Bolt: 110 Nm (81 lb-ft) + 125-degree turn
Chevrolet Malibu: 2014-2015 model years (Standard
engine).
Chevrolet Impala: 2014-2019 model years (Standard engine for Limited and base
models).
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