Opel A22DM Specifications
| Engine Model: Opel A22DM |
| Engine Type: 4-cycle 4-cylinder DOHC 16-valve turbocharged liquid-cooled diesel |
| Total Displacement: 136 cu.in (2.23 L) |
| Rated Engine Power: 163-184 Hp (120-135 kW) at 3800 rpm |
| Fuel System Type: Common rail direct injection |
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The Opel A22DM is a 2.2-liter, turbocharged inline-four
diesel engine produced from 2010 through 2015, representing a significant
evolution in General Motors’ diesel powertrain offerings for the European and
global markets. Developed under the GM family designation LNQ, this engine was
introduced with the facelifted Opel Antara to replace the aging 2.0-liter diesel
units, delivering improved power output, fuel efficiency, and emissions
compliance. The A22DM utilizes a common-rail direct injection system with
variable geometry turbocharging, enabling substantial torque delivery across a
wide engine speed range.
Constructed with a cast iron cylinder block and an aluminum alloy cylinder head,
the engine was engineered to meet Euro 5 emissions standards while providing the
durability required for sport utility vehicle applications. The A22DM was
offered in two power calibrations - a standard version and a high-output variant
designated A22DMH - allowing it to serve both mainstream and
performance-oriented configurations within the Antara and its platform sibling,
the Chevrolet Captiva.
The Opel A22DM is a four-stroke, water-cooled, inline-four diesel engine with a
total displacement of 2,231 cc (136 cu.in). The bore and stroke dimensions are
86.0 mm and 96.0 mm, respectively, creating an undersquare configuration that
emphasizes low-end torque production - a characteristic well-suited to sport
utility vehicle applications. The valvetrain employs a dual overhead camshaft
(DOHC) design with four valves per cylinder - two intake and two exhaust - for a
total of 16 valves. The camshafts are driven by a silent-type timing chain,
eliminating the replacement intervals associated with rubber timing belts.
Induction is provided by a variable geometry turbocharger (VGT) mounted to the
exhaust manifold, with compressed air routed through an air-to-air intercooler
to reduce intake charge temperature before entering the intake manifold. The
fuel system utilizes common-rail direct injection operating at pressures up to
1,800 bar (26,100 psi). The compression ratio is set at 16.3:1, a value selected
to balance cold-start capability with the elevated cylinder pressures associated
with common-rail combustion.
Power (Standard Version, A22DM): 120 kW (163 hp) at 3,800 rpm.
Torque (Standard Version, A22DM): 350 Nm (258 lb-ft) at 2,000 rpm.
Power (High-Output Version, A22DMH): 135 kW (184 hp) at 3,800 rpm.
Torque (High-Output Version, A22DMH): 400 Nm (295 lb-ft) at 2,000 rpm.
The engine speed limiter is set at 4,800 rpm.
The firing order is 1-3-4-2, the standard arrangement for inline-four engines.
The cylinder block is constructed from cast iron, a
material selected for its exceptional rigidity, acoustic damping properties, and
resistance to the high mechanical and thermal stresses inherent in modern diesel
combustion. The block utilizes a closed-deck design, where the cylinder bores
are surrounded by a continuous metal surface at the top of the block, enhancing
structural integrity and cylinder bore roundness under high cylinder pressures.
The inline-four configuration incorporates five main bearings supporting a
forged steel crankshaft with eight counterweights to minimize vibration and
bearing loads. The connecting rods are constructed from forged steel, specified
to withstand the elevated mechanical loads imposed by the high-output
common-rail system. Cylinder bores are precision-machined with a plateau honed
finish and fitted with replaceable, centrifugally cast wet-type cylinder liners.
These liners are pressed into the block and sealed with O-rings, allowing
coolant to circulate directly around the liners for efficient heat transfer. The
water jacket surrounds the cylinder liners completely, providing uniform cooling
to the combustion chamber region. Piston cooling is accomplished through oil
jets mounted in the crankcase, directing a continuous spray to the underside of
each piston crown - a critical feature for managing thermal loads under
sustained boost operation.
The cylinder head is manufactured from aluminum alloy,
providing reduced mass and enhanced heat dissipation while maintaining
compatibility with the cast iron block through a multi-layer steel head gasket.
The dual overhead camshaft (DOHC) arrangement positions the intake and exhaust
camshafts within the head, supported by five bearing journals. The intake
camshaft is equipped with variable valve timing (VVT) to optimize volumetric
efficiency across the engine speed range, improving low-end torque and high-rpm
power delivery.
Valves are arranged in a pent-roof combustion chamber configuration with a
narrow included valve angle to promote efficient flame propagation and
accommodate the centrally located fuel injector. Intake valves measure 28.0 mm
(1.10 in) in diameter, while exhaust valves measure 26.0 mm (1.02 in) in
diameter. Valve actuation is provided by roller finger followers that reduce
frictional losses compared to sliding designs.
Hydraulic lash adjusters are integrated into the cylinder head, maintaining zero
valve clearance throughout the engine’s operating life and eliminating the need
for periodic valve adjustment. The valve springs are of the double-coil type in
high-stress applications to ensure positive valve seating under the elevated
cylinder pressures of diesel combustion.
The combustion chamber incorporates a re-entrant bowl design in the piston
crown, optimized for the spray pattern of the common-rail injectors. The
cylinder head gasket is a multi-layer steel (MLS) design with precision
embossing, providing reliable sealing under the fluctuating thermal and
mechanical loads characteristic of turbocharged diesel operation.
The fuel system is a third-generation common-rail
direct injection system operating at pressures up to 1,800 bar (26,100 psi). A
high-pressure fuel pump, mounted to the engine and driven by the timing chain,
draws fuel from the chassis-mounted tank through a water-separating fuel filter
and delivers it to the common rail.
The common rail functions as a high-pressure accumulator, maintaining stable
fuel pressure for all four injectors. The fuel injectors are piezoelectric or
solenoid-type units depending on the production year, capable of multiple
injection events per combustion cycle - including pilot injections for noise
reduction and post-injections for diesel particulate filter regeneration.
The engine control unit (ECU) calculates injection timing, duration, and the
number of injection events based on inputs from the crankshaft position sensor,
camshaft position sensor, accelerator pedal position sensor, mass airflow
sensor, and exhaust gas recirculation (EGR) system feedback. The system employs
closed-loop control using the heated oxygen sensor and, where equipped, a
particulate matter sensor to maintain optimal combustion efficiency and
emissions compliance.
A fuel temperature sensor integrated into the high-pressure pump allows the
system to adjust injection parameters to maintain optimal combustion under
varying fuel temperatures. The fuel filter incorporates a water-in-fuel sensor
that alerts the driver when accumulated water must be drained.
The lubrication system is a full-flow, pressurized
circuit utilizing a gear-type or trochoid-type oil pump mounted within the front
timing case and driven directly by the crankshaft. The pump draws engine oil
from a baffled aluminum sump through a strainer screen before directing it
through a full-flow spin-on oil filter. An oil pressure relief valve maintains
system pressure within the specified range, with operating pressure at operating
speed between 3.0 bar (44 psi) and 5.0 bar (73 psi). The main oil gallery
distributes pressurized oil to the crankshaft main bearings, connecting rod
bearings, camshaft bearings, hydraulic lash adjusters, and the variable valve
timing actuator.
The piston cooling oil jets are integrated into the main oil gallery circuit,
directing a continuous spray to the underside of each piston crown. The total
engine oil capacity, including the filter, is approximately 5.6 L (5.9 qt).
Recommended oil specification is 5W-30 fully synthetic meeting GM dexos2
standards, formulated to withstand the thermal stresses of turbocharged diesel
operation and extended service intervals.
The cooling system operates as a pressurized,
thermostatically controlled water circulation circuit designed to manage the
substantial thermal output of the high-output diesel engine. A belt-driven
centrifugal water pump, mounted to the front of the cylinder block, circulates a
mixture of water and ethylene glycol antifreeze through the cylinder block,
cylinder head, turbocharger bearing housing, EGR cooler, and the main radiator.
Coolant flow is directed first to the cylinder block to provide even cooling
around the wet-type cylinder liners before ascending into the cylinder head. The
thermostat is a wax-pellet type positioned on the coolant inlet side of the
water pump, maintaining operating temperature within the range of 85°C to 95°C
(185°F to 203°F). The radiator is a cross-flow aluminum construction with
plastic end tanks, sized to accommodate the heat rejection requirements of the
2.2-liter diesel.
An electric cooling fan, controlled by the engine control unit based on coolant
temperature and air conditioning compressor operation, provides forced airflow
during low-speed operation or high ambient temperatures. An expansion tank
allows for coolant expansion and provides a point for air separation from the
system. The total cooling system capacity is approximately 9.0 L (9.5 qt) for
the complete system.
| Intake and Exhaust Systems |
Intake System: The intake manifold is constructed from
aluminum or composite material and incorporates the EGR mixer. The variable
geometry turbocharger (VGT) adjusts its turbine vanes electronically under ECU
control, varying the aspect ratio to provide rapid boost response at low rpm
while preventing overspeed at high rpm. The charge-air cooler is a front-mounted
air-to-air intercooler of sufficient capacity to reduce intake air temperatures
under sustained boost conditions.
Exhaust System: The exhaust manifold is integrated with the turbocharger housing
in a compact design that reduces weight and minimizes thermal losses. The
after-treatment system includes a diesel oxidation catalyst (DOC) and a diesel
particulate filter (DPF) mounted close to the engine to achieve rapid light-off.
Regeneration of the DPF is managed automatically through post-injection of fuel
during the exhaust stroke, raising exhaust temperatures to burn off accumulated
soot. A heated oxygen sensor is positioned upstream of the DOC, with pressure
sensors across the DPF monitoring filter loading.
EGR System: The engine incorporates a high-pressure
exhaust gas recirculation (EGR) system to reduce nitrogen oxide emissions. The
EGR cooler, integrated into the cooling circuit, reduces the temperature of
recirculated exhaust gases before they enter the intake manifold. An EGR valve,
electronically controlled by the ECU, modulates flow based on engine operating
conditions.
Timing Drive: The camshafts and the high-pressure fuel pump are driven by a
silent-type timing chain. The chain is lubricated by engine oil and guided by
tensioners and guides, with a hydraulic chain tensioner maintaining proper chain
tension throughout the engine’s operating life.
The overall length, measured from the front accessory
drive to the flywheel mating face, is 650 mm (25.6 in). Width across the
cylinder head, intake manifold, and turbocharger assembly is 680 mm (26.8 in).
Height from the bottom of the oil sump to the top of the cylinder head cover is
760 mm (29.9 in).
The dry weight of the engine, inclusive of the
turbocharger, intake and exhaust manifolds, alternator, starter motor,
and fuel system components but without transmission or fluids, is 170 kg
(375 lb), reflecting the robust cast iron block construction.
The engine oil and filter must be replaced at intervals
not exceeding 15,000 km (9,321 mi) or 12 months under normal operation, using a
synthetic oil meeting GM dexos2 specification. Severe duty applications,
including frequent towing or short trips, require a reduced interval of 10,000
km (6,214 mi). The timing chain requires no scheduled replacement but should be
inspected for noise and tensioner function at major service intervals.
The fuel filter incorporates a water separator and requires replacement every
30,000 km (18,641 mi) or as indicated by the water-in-fuel warning lamp. The air
filter element should be inspected at each oil change and replaced every 30,000
km (18,641 mi) to 40,000 km (24,855 mi) depending on operating conditions.
Coolant replacement is specified at 60,000 km (37,282 mi) or every five years,
utilizing a long-life antifreeze formulation.
Cylinder Head Bolts: Stage one: 40 Nm (30 lb-ft).
Main Bearing Cap Bolts: 50 Nm (37 lb-ft).
Connecting Rod Cap Bolts: 30 Nm (22 lb-ft).
Camshaft Bearing Caps: 12 Nm (9 lb-ft).
Flywheel Bolts: 90 Nm (66 lb-ft).
Crankshaft Pulley Bolt: 200 Nm (148 lb-ft).
Intake Manifold Bolts: 22 Nm (16 lb-ft).
Exhaust Manifold Nuts: 30 Nm (22 lb-ft).
Turbocharger Mounting Nuts: 40 Nm (30 lb-ft).
High-Pressure Fuel Pump Mounting Bolts: 25 Nm (18 lb-ft).
Fuel Injector Clamp Bolts: 25 Nm (18 lb-ft).
Oil Pan Bolts: 12 Nm (9 lb-ft).
Timing Chain Tensioner Bolt: 25 Nm (18 lb-ft).
EGR Valve Mounting Bolts: 12 Nm (9 lb-ft).
Engine Mounting Brackets: 70 Nm (52 lb-ft).
The Opel A22DM engine was deployed primarily in sport
utility vehicle platforms where its combination of torque, fuel efficiency, and
emissions compliance met the demands of the segment.
Opel Antara A (Facelift, 2010-2015): The A22DM served as the exclusive diesel
power unit for the facelifted Antara, replacing the previous 2.0-liter diesel.
The engine was offered in both standard 163 hp (120 kW) and high-output 184 hp
(135 kW) calibrations, paired with a six-speed automatic transmission in
front-wheel drive and all-wheel drive configurations.
Vauxhall Antara: The engine was carried over under the Vauxhall brand in the
United Kingdom, with identical specifications to the Opel variant.
Chevrolet Captiva: The same engine, designated under the GM code LNQ, was
utilized in the Chevrolet Captiva - the Antara’s platform sibling - for markets
outside Europe, including South America, Australia, and the Middle East. In this
application, the engine was offered with both the standard and high-output
calibrations depending on market and trim level.
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