John Deere 6059T Specifications
| Engine Model: John Deere 6059T |
| Engine Type: 4-stroke in-line 6-cylinder turbocharged liquid-cooled diesel |
| Total Displacement: 359 cu.in (5.9 L) |
| Rated Engine Power: 115-150 Hp (86-112 kW) at 2500 rpm |
| Fuel System Type: Direct Injection |
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The John Deere 6059T is a 5.9-liter,
turbocharged, inline six-cylinder diesel engine produced by John Deere
Power Systems. This engine belongs to the venerable 60 Series engine
family, a platform renowned for its durability, serviceability, and high
torque rise characteristics suited for agricultural, construction, and
industrial applications. The 6059T represents a naturally aspirated 6059
base engine enhanced with a turbocharger to increase volumetric
efficiency and power output without a corresponding increase in
displacement or engine speed.
The engine employs a direct injection fuel system with a rotary
distributor pump, a design choice that balances fuel efficiency with
mechanical simplicity. A defining characteristic of the 6059T is its
replaceable wet-sleeve cylinder liner construction, which permits engine
rebuilding in the field without removing the engine from the chassis or
performing complex block machining operations. The crankshaft rides on
seven main bearings, providing exceptional support for the long stroke
and high cylinder pressures generated by turbocharging.
John Deere engineered this engine for a low rated speed range of 2,100
to 2,500 rpm, prioritizing torque rise and lugging ability at the
expense of maximum horsepower. This torque characteristic allows the
engine to maintain rotational speed under increasing load, a valuable
trait for tractor tillage and combine harvesting operations. The 6059T
found widespread application in John Deere 7000 series tractors, 544G
wheel loaders, and 9400 series combines, where it delivered thousands of
hours of operation between overhauls.
The John Deere 6059T is a four-stroke, compression-ignition, inline
six-cylinder diesel engine. The induction system employs a single
turbocharger without an aftercooler or intercooler on most variants.
Total displacement measures 359 cubic inches, equivalent to 5.9 liters.
The bore dimension is 4.19 inches (106.5 mm), and the stroke dimension
is 4.33 inches (110.0 mm).
This near-square bore-to-stroke ratio provides a balance of low-end
torque production and high-rpm breathing. The compression ratio is fixed
at 17.8:1. The firing order sequence is 1-5-3-6-2-4, a standard
configuration for inline six-cylinder engines that produces perfect
primary and secondary balance without requiring balance shafts. Engine
rotation, viewed from the flywheel end, is counterclockwise. Rated power
output ranges from 86 kW to 112 kW (115 hp to 150 hp) depending on the
specific application, fuel injection pump calibration, and governed
speed setting.
Peak torque reaches 475 Nm to 530 Nm (350 lb-ft to 390 lb-ft) at an
engine speed of 1,400 to 1,600 rpm. The rated engine speed for most
agricultural applications is 2,100 to 2,500 rpm, selected by the
operator via the hand throttle. Low idle speed is set between 800 and
950 rpm, depending on the governor adjustment and application.
The cylinder block is constructed from high-strength cast iron with a
deep-skirt design extending below the crankshaft centerline. This
configuration provides maximum rigidity to resist bending and torsional
loads encountered during heavy tillage or loader work. A defining
engineering feature of the 6059T block is its wet-sleeve cylinder liner
design.
Each of the six cylinders contains a removable, replaceable sleeve
manufactured from centrifugally cast iron. The outer diameter of each
sleeve contacts the engine coolant directly, a configuration that
provides superior heat transfer from the combustion zone to the cooling
system. The liners are held in place by the cylinder head gasket when
the head is torqued to specification, eliminating the need for a lower
liner seal in most applications.
An upper liner seal, usually an O-ring or rectangular-section seal,
prevents coolant leakage between the liner flange and the block
counterbore. The block incorporates a seven-main-bearing crankshaft
support structure, meaning the crankshaft rotates on seven bearing
journals. This arrangement, with six connecting rod journals positioned
between the seven main bearings, minimizes crankshaft deflection under
high cylinder pressure loads. The cylinder block casting includes
integral mounting pads for the fuel injection pump, water pump, and
front timing gear cover.
The cylinder head is a separate cast-iron component bolted to the top of
the cylinder block using a single-piece head gasket. The head houses the
overhead valve (OHV) mechanism and the precombustion chamber inserts on
certain indirect injection variants, though the 6059T predominantly uses
a direct injection design with a shallow re-entrant combustion bowl
machined directly into the piston crown.
The valvetrain is actuated by a camshaft located within the cylinder
block, driven by a gear train from the crankshaft. Camshaft lobes
contact mechanical lifters (tappets), which push hollow pushrods upward.
The pushrods transmit motion to forged steel rocker arms mounted on a
shaft, which pivot to open the valves against spring pressure. The
cylinder head contains two valves per cylinder, one intake and one
exhaust, for a total of twelve valves. Intake and exhaust valves are
positioned in a straight line along the cylinder head.
The valve seat inserts are replaceable, a serviceability feature that
allows head reconditioning without complete replacement. Valve lash
(clearance) is adjustable via set screws on the rocker arms.
Specification for intake valves, measured with the engine cold, ranges
from 0.20 mm to 0.36 mm (0.008 in to 0.014 in) depending on the
production series. Exhaust valve lash, also measured cold, ranges from
0.36 mm to 0.48 mm (0.014 in to 0.019 in). The crossflow design
positions the intake manifold on one side of the head and the exhaust
manifold on the opposite side, reducing heat transfer from the exhaust
to the intake charge.
The fuel system employs a mechanical direct injection design without
electronic controls. The injection pump is a Stanadyne (Roosa Master)
DB2 or DB4 series rotary distributor pump, mounted on the side of the
cylinder block and gear-driven from the camshaft. This pump uses a
single pumping plunger to distribute fuel to each cylinder in the
correct firing order.
A mechanical flyweight governor, internal to the injection pump, senses
engine speed and adjusts fuel delivery to maintain the selected governed
speed under varying loads. The governor incorporates both low-idle and
high-speed limiting circuits. A fuel transfer pump, mounted on the
injection pump housing, draws fuel from the tank through a primary
filter (water separator) and delivers it to the injection pump inlet.
The injection pump pressurizes fuel to approximately 1,500 to 2,000 psi
and distributes it to individual injection lines.
These steel lines carry high-pressure fuel to the injection nozzles
(injectors) mounted in the cylinder head. The injectors are of the
pencil-type design with a spring-loaded needle valve. Injector opening
pressure is factory set between 180 bar and 200 bar (2,600 psi and 2,900
psi). Excess fuel not injected returns to the fuel tank via a
low-pressure return line. A manual shutoff lever on the injection pump
allows mechanical stopping of the engine by cutting fuel delivery.
The lubrication system is a pressurized, wet-sump design using a
gear-type oil pump. The oil pump is mounted inside the timing gear cover
and driven directly by the crankshaft gear. A suction pipe extends from
the pump into the oil pan, drawing oil through a wire-mesh strainer.
After pressurization, oil passes through a full-flow oil filter mounted
externally on the cylinder block. The filter element is a spin-on,
replaceable canister type.
From the filter, oil travels through internal drillings in the cylinder
block to reach the seven main bearings. Drilled passages within the
crankshaft direct oil from the main bearings to the connecting rod
bearings. Excess oil from the main bearings and camshaft bearings is
directed upward through vertical passages to lubricate the valve train,
including the camshaft lobes, lifters, pushrod ends, and rocker arms.
The system capacity ranges from 13.0 to 19.0 liters (13.7 to 20.0 US qt)
depending on the oil pan configuration.
Standard deep-sump pans hold the higher capacity, while shallow pans for
low-clearance applications hold the lower capacity. Operating oil
pressure at rated engine speed should register between 35 psi and 50 psi
(240 kPa and 345 kPa). A pressure relief valve, located near the oil
pump outlet, opens at approximately 60 psi (414 kPa) to prevent
excessive pressure during cold starts. A piston-cooling oil jet is not
present on most 6059T variants, as cylinder temperatures remain
manageable at the specified power levels.
The cooling system is a pressurized, pump-circulated water system. A
centrifugal water pump is belt-driven from the crankshaft pulley.
Coolant flows from the lower radiator hose into the water pump, through
the cylinder block water jacket, upward into the cylinder head, and then
out through the upper radiator hose. The wet-sleeve liner design exposes
the full length of each cylinder liner to coolant flow, providing
uniform cylinder temperature and reducing bore distortion.
A wax-pellet thermostat regulates operating temperature. The thermostat
is located in a housing at the front of the cylinder head. The rated
opening temperature is 82°C (180°F). A bypass circuit allows coolant to
circulate within the engine block and head when the thermostat is
closed, preventing localized hot spots during warm-up.
A coolant recovery tank connects to the radiator overflow tube. The
total cooling system capacity, engine only (excluding radiator and
hoses), is 12.0 to 14.0 liters (12.7 to 14.8 US qt). A belt-driven fan
with a thermostatic fan clutch is standard on most applications to
reduce parasitic power loss when cooling demand is low.
| Intake and Exhaust Systems |
Air Intake System: Air enters through a dry-type, two-stage air cleaner.
The turbocharger compressor draws filtered air, compresses it, and
delivers it to the intake manifold. The intake manifold distributes air
evenly to all six cylinders.
Exhaust System: Exhaust gases exit each cylinder through the exhaust
manifold, which collects gases into a single pipe feeding the
turbocharger turbine housing. Exhaust gases spinning the turbine wheel
provide the power to drive the compressor wheel. After leaving the
turbine, exhaust passes through a muffler and tailpipe.
The electrical system is 12-volt negative ground on standard
applications, with optional 24-volt systems available for cold climate
or military applications. A gear-reduction starter motor engages with
the flywheel ring gear. A belt-driven alternator charges the battery.
Glow plugs are installed in the cylinder head for cold starting
assistance. Glow plug operating voltage is 12 volts, with a preheat time
of 5 to 10 seconds depending on ambient temperature. An intake air
heater may be fitted as an alternative cold start aid on some variants.
The complete engine assembly, including the turbocharger, injection
pump, manifolds, alternator, starter, and flywheel housing, has an
overall length of 1,106 mm (43.5 in), a width of 605 mm (23.8 in), and a
height of 950 mm (37.4 in). The dry weight of the long block (cylinder
block with crankshaft, pistons, connecting rods, camshaft, and cylinder
head) is 522 kg (1,150 lb). The full dressed weight, including all
accessories, fluids, and the flywheel, approaches 590 kg (1,300 lb).
Engine oil and filter should be changed every 250 hours under normal
conditions and every 150 hours under severe duty (heavy dust, high load
factor, or extreme temperatures). Oil viscosity selection follows API
service classification CF-4 or higher. Recommended viscosities are SAE
15W-40 for year-round use above -10°C (14°F) and SAE 10W-30 for winter
operation below -10°C. The fuel filter (primary water separator and
secondary spin-on filter) requires replacement every 500 hours.
The air cleaner primary element requires cleaning every 250 hours and
replacement every 1,000 hours. The safety (secondary) air cleaner
element requires replacement every 500 hours. Valve lash adjustment is
required every 1,000 hours. The cooling system requires draining,
flushing, and refilling with a fresh mixture of ethylene glycol
antifreeze and distilled water (50/50 ratio) every 2,000 hours or two
years.
The thermostat replacement interval is 2,000 hours. The water pump
bearing requires no maintenance, being a sealed unit. The turbocharger
bearing requires no separate lubrication, receiving oil from the engine
lubrication system. The injection pump timing should be checked every
2,000 hours. The fuel injectors require testing and recalibration every
2,500 hours.
Cylinder head bolts receive a final torque of 150 Nm (110 lb-ft) using a
crosswise sequence from the center outward. An angle tightening method
is not required on this engine. Connecting rod cap bolts are torqued to
90 Nm (65 lb-ft). Main bearing cap bolts receive 115 Nm (85 lb-ft).
Flywheel bolts are tightened to 115 Nm (85 lb-ft).
The crankshaft front pulley bolt is torqued to 450 Nm (330 lb-ft). The
camshaft thrust plate bolts receive 25 Nm (18 lb-ft). Rocker arm shaft
bracket nuts are secured to 50 Nm (37 lb-ft). Intake manifold bolts
receive 30 Nm (22 lb-ft). Exhaust manifold nuts are torqued to 45 Nm (33
lb-ft).
The injection pump mounting nuts receive 25 Nm (18 lb-ft). The injector
hold-down nuts are torqued to 25 Nm (18 lb-ft). The oil filter canister
requires tightening to 25 Nm (18 lb-ft) or one full turn after gasket
contact. The oil drain plug is torqued to 50 Nm (37 lb-ft). The water
pump mounting bolts receive 30 Nm (22 lb-ft). The fan drive pulley bolts
are set to 45 Nm (33 lb-ft).
0The John Deere 6059T engine powered a wide range of agricultural,
construction, and industrial equipment. Primary tractor applications
include the John Deere 7200, 7400, and 7600 series row-crop tractors
produced throughout the 1990s. In these tractors, the 6059T served as
the mid-range power option between the naturally aspirated 6059 and the
larger 6076T engine.
The engine also appeared in the John Deere 6400 and 6600 series utility
tractors. Construction equipment applications include the John Deere 690
series hydraulic excavators, the 544G wheel loader, and the 640 and 648
series grapple skidders for forestry operations. Agricultural harvesting
applications include the John Deere 9400 and 9500 series combines, where
the engine provided power for both propulsion and threshing systems.
Self-propelled sprayers, including the John Deere 4700 series, also
utilized the 6059T.
A naturally aspirated version of this engine, without the turbocharger,
exists as the John Deere 6059D. A higher-output variant with an
aftercooler, intercooled for reduced intake air temperature, exists as
the John Deere 6059T with air-to-air aftercooling. The 6059T is distinct
from the larger John Deere 6076T (7.6-liter) and the later PowerTech
6068T (6.8-liter) engines, which share the same basic architecture but
differ in bore and stroke dimensions.
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