Mitsubishi 4D56T Specifications
| Engine Model: Mitsubishi 4D56T |
| Engine Type: 4-cycle inline 4-cylinder SOHC 8-valve turbocharger liquid-cooled diesel |
| Total Displacement: 151.2 cu.in (2.47 L) |
| Rated Engine Power: 99-115 Hp (74-85 kW) at 4000 rpm |
| Fuel System Type: Indirect injection |
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The Mitsubishi 4D56T is the turbocharged variant of the
2.5-liter Astron diesel engine, introduced in 1986. Serving as the workhorse for
Mitsubishi’s light commercial and off-road vehicle lineup, the 4D56T powered the
Pajero, L200 (Triton), Delica, and L300 across multiple generations. The engine
is characterized by its cast iron construction, indirect injection with a swirl
chamber, and a single overhead camshaft (SOHC) operating two valves per
cylinder.
Later iterations evolved into a 16-valve common rail configuration designated
DI-D, though the original 8-valve turbocharged variant remained in production
for decades due to its simplicity, durability, and ease of service in demanding
operating environments.
Engine Type: Inline 4-cylinder, 4-cycle, water-cooled, turbocharged diesel.
Displacement: 2,477 cc (151.2 cu.in).
Bore: 91.1 mm (3.59 in).
Stroke: 95.0 mm (3.74 in).
Compression Ratio: 21.0:1.
Valvetrain Configuration: Single Overhead Camshaft (SOHC), 8 valves (2 per
cylinder).
The camshaft is driven by a toothed timing belt.
Firing Order: 1-3-4-2.
Maximum Power Output: 99-115 hp (74-85 kW) @ 4,000 rpm.
Maximum Torque Output: 240 Nm (177 lb-ft) @ 2,000 rpm.
Aspiration: Turbocharged with an exhaust-driven turbocharger.
Intercooled variants utilize an air-to-air charge cooler mounted in the front
grille area.
Boost Pressure: 0.6-0.8 bar (8.7-11.6 psi) for standard variants.
The cylinder block is manufactured from cast iron with
a deep-skirt design extending below the crankshaft centerline. Bore diameter
measures 91.1 mm (3.59 in). The block features a closed-deck design with
pressed-in cast iron cylinder liners that are replaceable during major
overhauls. The crankshaft is forged steel with eight counterweights, supported
by five main bearings.
The block incorporates dual balance shafts mounted within the crankcase to
reduce secondary vibrations, driven by a separate toothed belt. The balance
shafts rotate at twice engine speed in opposite directions. Compression pressure
specification is 3.04 MPa (441 psi) for a new engine, with a minimum service
limit of 2.26 MPa (327 psi). Dry weight is 210 kg (463 lb).
The cylinder head is manufactured from cast iron,
matching the block material to ensure uniform thermal expansion under high
cylinder pressures.
Valves: 8 total; 4 intake, 4 exhaust.
Intake Valve Diameter: 35.0 mm (1.38 in).
Exhaust Valve Diameter: 32.0 mm (1.26 in).
Valve Stem Diameter: 8.0 mm (0.31 in) for both intake and exhaust.
Valve Seat Inserts: Press-fit inserts; exhaust valve seats are manufactured from
heat-resistant alloy.
Valve Guides: Cast iron guides pressed into the cylinder head.
Valve Adjustment: Mechanical adjusters with threaded rocker arms and lock nuts.
Valve clearance is set with the engine hot (operating temperature). Intake
clearance: 0.25 mm (0.010 in); Exhaust clearance: 0.25 mm (0.010 in). Adjustment
interval is 40,000 km (25,000 miles). Camshaft: Chilled cast iron camshaft with
induction-hardened lobes, supported by four bearings and driven by a toothed
timing belt.
Combustion Chamber: Indirect injection configuration utilizing a swirl chamber
(pre-combustion chamber) cast into the cylinder head. Fuel is injected into the
swirl chamber where partial combustion occurs before flame propagates into the
main combustion chamber. This design allows for smooth combustion and reduced
mechanical noise.
Glow Plugs: Pencil-type glow plugs with rapid heating capability. Pre-heat
duration ranges from 4-12 seconds depending on ambient temperature. A glow plug
control unit manages pre-heating and post-heating cycles.
The fuel system employs a mechanical in-line injection
pump with indirect injection through swirl chambers. Injection Pump Type: Bosch
or Zexel mechanical in-line pump with a mechanical governor. The pump is driven
by the timing belt from the crankshaft. Injectors: Mechanical pintle-type
injectors with an opening pressure of 110-120 bar (1,595-1,740 psi). Injectors
are connected to the injection pump by individual high-pressure steel lines.
Fuel Filtration: Spin-on cartridge fuel filter with an integrated water
separator and manual priming pump. Fuel Pressure: Injector opening pressure is
110-120 bar (1,595-1,740 psi). The mechanical fuel lift pump, operated by an
eccentric lobe on the camshaft, supplies fuel to the injection pump at low
pressure.
Cold Start Device: Manual or automatic cold start advance mechanism that adjusts
injection timing to compensate for lower combustion temperatures during engine
warm-up. A cable-operated device on the injection pump is used on early
variants; later variants incorporate a thermostatic or vacuum-actuated system.
Engine Shutdown: Mechanical shut-off lever on the injection pump operated by a
cable or solenoid.
0The lubrication system is a full-flow, pressurized
design utilizing a rotor-type oil pump driven by the crankshaft. Oil Pump Type:
Internal gear (gerotor) pump mounted to the front of the crankshaft, housed
within the front timing cover assembly. Oil Capacity: 6.5-7.5 liters (6.9-7.9
qt) including oil filter replacement. Capacity varies with the presence of an
oil cooler and sump configuration. Recommended Oil Viscosity: 15W-40 or 10W-40
for standard operating conditions; 5W-30 for colder climates.
Oil Quality Requirement: API CD, CE, CF, or later diesel-specific
classifications. Oil Pressure: At warm idle, pressure ranges from 0.8-1.5 bar
(12-22 psi). At 3,000 rpm, pressure reaches 3.5-4.5 bar (51-65 psi). Oil Cooler:
Liquid-to-oil plate-type heat exchanger mounted between the oil filter and
cylinder block on intercooled variants and certain commercial applications.
Oil Filter: Full-flow spin-on canister type mounted to the cylinder block. The
filter incorporates a bypass valve to maintain oil flow if the filter element
becomes restricted. Crankcase Ventilation: Closed system with a breather hose
routed from the valve cover to the air intake duct upstream of the turbocharger.
The cooling system is pressurized and utilizes a
centrifugal water pump driven by the timing belt or accessory belt depending on
variant. Water Pump Type: Centrifugal pump with a cast iron housing and stamped
steel impeller. Thermostat: Wax-pellet type located in the coolant outlet
housing. Opening temperature is 76.5-82.5C (170-180F) for standard variants;
82-88 °C (180-190 °F) for intercooled variants.
Coolant Capacity: 7.5-9.0 liters (7.9-9.5 qt) inclusive of engine block, heater
core, and radiator. System Pressure: Radiator cap rated at 0.9-1.1 bar (13-16
psi). Coolant Specification: Ethylene glycol-based coolant with corrosion
inhibitors suitable for cast iron engine construction.
Radiator: Cross-flow aluminum core with plastic end tanks. Cooling fan
configuration consists of an engine-driven mechanical fan with a viscous clutch
on most applications; later variants utilize dual electric fans.
Timing System: Dual-belt configuration. A primary
toothed timing belt drives the camshaft and injection pump from the crankshaft.
A secondary toothed belt drives the dual balance shafts. Automatic spring-loaded
tensioners maintain belt tension on both systems. Timing belt replacement
interval is 100,000 km (60,000 miles) or 5 years.
Turbocharger System: Single turbocharger with fixed geometry, manufactured by
Mitsubishi Heavy Industries (MHI). The turbocharger is oil-lubricated and
water-cooled on intercooled variants. Wastegate actuation is pneumatic,
controlled by boost pressure.
Exhaust System: Cast iron exhaust manifold with integrated turbocharger mounting
flange. A single catalytic converter is present on later variants; early export
variants utilize a catalytic converter for emissions compliance.
Intake Manifold: Cast iron or aluminum manifold with individual runners per
cylinder. Intercooled variants incorporate an air-to-air charge cooler mounted
in the front grille area.
Starting System: 12-volt electric starter with a heavy-duty solenoid. Glow plug
pre-heating is required before cold starts.
Overall Length: 680 mm (26.8 in) measured from
accessory drive pulley face to transmission mounting flange.
Overall Width: 620 mm (24.4 in) inclusive of injection pump, intake manifold,
and turbocharger assembly.
Overall Height: 750 mm (29.5 in) from oil pan bottom surface to valve cover top
surface.
Dry Weight: 205-215 kg (452-474 lb) depending on turbocharger configuration and
intercooler plumbing.
Valve Clearance (hot): Intake 0.25 mm (0.010 in);
Exhaust 0.25 mm (0.010 in). Adjustment interval is 40,000 km (25,000 miles).
Timing Belt Replacement Interval: 100,000 km (60,000 miles) or 5 years. Both
primary timing belt and balance shaft belt must be replaced concurrently.
Injection Pump Timing: Static injection timing set to 7°-9° BTDC for standard
variants. Timing is adjusted by shim selection on the injection pump mounting
flange.
Injector Opening Pressure: 110-120 bar (1,595-1,740 psi). Inspection interval is
40,000 km (25,000 miles). Glow Plug Replacement Interval: Replace as required;
resistance testing recommended at 40,000 km (25,000 miles). Drive Belt Tension
(Accessory): 10-12 mm (0.39-0.47 in) deflection under 10 kg (22 lb) of force at
the midpoint of the longest span. Coolant Change Interval: 40,000 km (25,000
miles) or 2 years.
Engine Oil Change Interval: 5,000-7,500 km (3,100-4,700 miles) depending on
operating conditions and oil quality. Idle Speed (warm, neutral): 700-750 rpm.
Fuel Filter Change Interval: 20,000 km (12,500 miles) or as indicated by
water-in-fuel sensor. Compression Pressure: Standard 3.04 MPa (441 psi); Minimum
2.26 MPa (327 psi). Maximum variation between cylinders is 0.29 MPa (42 psi).
Cylinder Head Bolts (cold), Step 1: 30-35 Nm (22-26
lb-ft).
Cylinder Head Bolts (cold), Step 2: 60-70 Nm (44-52 lb-ft).
Cylinder Head Bolts (cold), Step 3: 105-115 Nm (77-85 lb-ft).
Crankshaft Damper Pulley Bolt: 170-190 Nm (125-140 lb-ft).
Connecting Rod Cap Nuts: 45-48 Nm (33-35 lb-ft).
Main Bearing Cap Bolts: 75-85 Nm (55-63 lb-ft).
Camshaft Bearing Cap Bolts: 20-25 Nm (15-18 lb-ft).
Camshaft Sprocket Bolt: 70-80 Nm (52-59 lb-ft).
Valve Cover Nuts: 8-10 Nm (6-7 lb-ft).
Rocker Arm Shaft Bolts: 20-25 Nm (15-18 lb-ft).
Intake Manifold Nuts: 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts: 30-35 Nm (22-26 lb-ft).
Turbocharger Mounting Nuts: 40-45 Nm (30-33 lb-ft).
Oil Pan Bolts: 10-12 Nm (7-9 lb-ft).
Oil Pump Mounting Bolts: 10-12 Nm (7-9 lb-ft).
Timing Belt Tensioner Bolts: 20-25 Nm (15-18 lb-ft).
Balance Shaft Belt Tensioner Bolt: 20-25 Nm (15-18 lb-ft).
Water Pump Bolts: 20-25 Nm (15-18 lb-ft).
Injection Pump Mounting Nuts: 20-25 Nm (15-18 lb-ft).
Injection Line Fittings: 20-25 Nm (15-18 lb-ft).
Injector Hold-Down Clamps: 30-35 Nm (22-26 lb-ft).
Flywheel / Drive Plate Bolts: 130-140 Nm (96-103 lb-ft).
Glow Plugs: 20-25 Nm (15-18 lb-ft).
Mitsubishi Pajero (V20, V30, V40 series): 1986-2006.
The 4D56T powered the short-wheelbase and long-wheelbase variants across
multiple generations, serving as the primary diesel powertrain for markets
outside Japan.
Mitsubishi L200 / Triton (K00, K10, K30 series): 1986-2005. The engine was
utilized in light-duty and heavy-duty pickup truck configurations, with
intercooled variants appearing in later models.
Mitsubishi Delica (L300, L400 series): 1986-2005. The 4D56T powered the Delica
van and wagon in both two-wheel-drive and four-wheel-drive configurations.
Mitsubishi L300 (P-series): 1986-2013. The 4D56T was installed in the L300
commercial van and minibus across global markets, with production continuing in
certain regions through the 2010s.
Mitsubishi Pajero Sport / Challenger (K90, K100 series): 1996-2005. The 4D56T
served as the diesel powertrain for the SUV variant derived from the L200
platform.
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