PDF Service Manual Mack Truck MP8 (EURO 4) Diesel Engine - 5 MB
This is the official service manual for the Mack MP8 EURO 4 diesel engine.
It is a vital resource for mechanics performing diagnostics, repairs, or complete overhauls.
The manual includes detailed specifications, torque values, and step-by-step instructions for disassembly and reassembly.
Ensure your Mack engine is serviced to factory standards with this comprehensive document.
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MACK MP8
®
DIESEL ENGINE
SERVICE MANUAL JULY 2009
(EURO 4)
(REVISED)
5-117
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INTRODUCTION
The MP8 uses unit injectors. The unit injector
incorporates the pump, valve and injector. Its
internal solenoids permit fast, precise control of
Do NOT use starting fluid (ether) on engines fuel delivery into the cylinder. The unit injectors
equipped with an inlet manifold air heater are encased by the valve cover and not exposed
element. An explosion could occur. Failure to to the heat of exhaust system components.
heed this danger may result in severe
personal injury or death. Replacing injectors requires a specific procedure,
and installation requires that the EECU be
programmed to recognize replacement injectors.
Two optional fan drives are available: On/Off and
Cleaning injector bores requires a special tool.
electronically actuated. The electronically
actuated viscous fan drive is precisely controlled
An engine compression brake option on the MP8
by the Engine Electronic Control Unit (EECU).
engine assists deceleration and braking. The
operation of the brake differs from earlier engine
models. Working in conjunction with the exhaust
cycle, the brake requires a camshaft with four
The electronically actuated fan drive is not cams per cylinder, two rocker arms for the
available on vehicles manufactured for Australia. exhaust valves, a bridge over the two exhaust
valves, an electronic control valve and a wiring
harness that includes the control valve. The
Timing gears mount on the rear of the MP8
exhaust valves are adjusted with shims.
improving the flow of cooling air around the front.
Special service instructions apply to the camshaft
Preventive maintenance is important to get the
position sensor. The mounting plate, idler and
most from the MACK MP8 engine and to ensure
camshaft gears are marked to facilitate proper
many years of reliable, trouble-free operation.
installation. The air compressor drive gear
Refer to the current TS943 Maintenance and
meshes with the double idler instead of the
Lubrication manual for schedules and
auxiliary idler as on the MP7 engine.
specifications.
Another feature of the MP8 is the rear engine
Repair instructions in this manual deal with
power take-off (REPTO-ready) that is gear driven
removal, installation, disassembly, assembly,
through the timing gear train. An optional PTO
setup and adjustments of MP8 components.
with drive gear, bearing and housing can be
added at the factory.
There are restrictions concerning the reuse of
certain fasteners. Refer to current specifications
The rocker arm shaft is held in place by camshaft
bulletins and the SPECIFICATIONS section of
bearing capscrews. There are special instructions
this manual for detailed information.
for installing the camshaft bearing caps and the
rocker arm shaft during service.
A stiffener plate fastens to the bottom of the
cylinder block to ensure block strength and
rigidity. The engine can be used with axle forward
or axle back vehicles by virtue of optional oil
pans. The engine fan is mounted high or low
depending on vehicle configuration.
Page 10
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DESCRIPTION AND OPERATION
OIL PAN The oil pan includes an oil level/temperature
sensor with connector. The filler tube and dipstick
The oil pan is plastic or steel with a threaded plug
mounting ports are also components of the oil
for draining. The plastic pan has a groove in the
pan.
mounting flange which accepts a molded
elastomer gasket for a seal. The steel pan is
sealed with a gasket on the oil pan flange.
Twenty-two spring-loaded screws clamp the pan
to the block. Oil pans with the sump at the front or at the rear
12 are available to accommodate axle forward or
axle back chassis.
CRANKSHAFT
The crankshaft is drop forged steel and induction
hardened. It has seven journals with replaceable
bearings. Five oversized replacement bearing
options are available to accommodate crankshaft
regrinding.
The rear main cap (No. 7) includes an attaching
point for the lube pump. Thrust washers to control
axial movement straddle the central journal (cap
No. 4). The remaining caps (Nos. 1–3, 5 and 6)
are numbered to facilitate correct assembly.
Figure 12 — Oil Pan and Stiffener Plate
1. Block Stiffener Plate 2. Oil Pan with Gasket
13
Figure 13 — Crankshaft, Bearings, Thrust Washers and Cap Alignment Tabs
1. Alignment Tab, Block 3. Thrust Washers
2. Alignment Tab, Cap 4. Upper and Lower Bearings
Page 20
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DESCRIPTION AND OPERATION
UNIT INJECTORS
23
Figure 23 — Unit Injector Diagram
1. Injector Yoke 8. Solenoid Coil
2. Copper Sleeve 9. Solenoid Coil
3. O-Ring 10. Injector Valve
4. Fuel Gallery 11. Injector Piston
5. O-Ring 12. Injector Nozzle
6. O-Ring 13. Washer
7. Pressure Relief Valve
This engine uses double solenoid unit injectors. The fuel pump pressurizes the gallery so that fuel
Unlike systems that require separate components rushes into each injector when it opens. Gallery
for delivering, pressurizing and injecting, this unit pressure is regulated by a valve that delivers
injector combines these functions. These excess fuel back to the tank.
injectors precisely control the fuel delivery
because of the two solenoids. The solenoids, Copper sleeves, acting as coolant jackets, line
pump and nozzle are in a single body in close the bottoms of the injector bores. Engine coolant
proximity to each other. circulates around these sleeves aiding the
process of controlling injection temperature.
The injector is set in a pressurized fuel gallery
where the fuel temperature is constant. Uniform
fuel temperature means uniform quantity in each
injection which means uniform power output from
each cylinder.
Page 30
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DESCRIPTION AND OPERATION
GLOSSARY OF TERMS Exhaust Gas Recirculation (EGR)
A system whereby a pre-determined amount of
Atmospheric Pressure Sensor exhaust gas is returned to the combustion
A sensor incorporated into the EECU that detects chambers. Adding a small percentage of exhaust
atmospheric (barometric) pressure and relays gas to the fuel/air mixture lowers the combustion
this value to the EECU. This pressure is affected temperature reducing the formation of nitrogen
by altitude. oxides (NOx).
Carbon Monoxide (CO) Hydrocarbons (HC)
An odorless, colorless gas resulting from Chemical compounds composed only of carbon
incomplete combustion of hydrocarbons; found in and hydrogen. Gasoline, diesel fuel and motor oil
diesel truck exhaust; poisonous to humans and are all examples of a very large group of
animals. hydrocarbons. The largest source of
hydrocarbons is petroleum.
Compressor Discharge Temperature Sensor
Idler Gear
Mounted between the turbocharger compressor
housing and CAC, detects compressor discharge A gear running between a driving and a driven
air temperature and relays this value to the gear to make the driven gear rotate in the same
EECU. direction as the driving gear.
Cooled Exhaust Gas Recirculation (CEGR) Idler Tensioner
A system whereby a pre-determined amount of A belt tensioning device designed to maintain
exhaust gas is diverted through a heat exchanger optimum tension under varying engine speeds
where it is cooled and sent to the inlet manifold and load.
for introduction into the combustion chambers.
Adding the cooled exhaust gases to the Intake Air Temperature and Humidity Sensor
combustible fuel and air mixture lowers the Mounted in the air intake between the air cleaner
overall combustion temperatures for reduced and the turbocharger compressor housing,
formation of nitrogen oxides (NOx). detects outside air temperature and humidity and
relays these values to the EECU.
Electronic Unit Injector (EUI)
Controlled electronically by the EECU, there is Oxides of Nitrogen (NOx)
one electronic unit injector for each cylinder of an High temperatures and pressures of combustion
engine. A unit injector incorporates the pump, the produce oxides of nitrogen (NOx). When
injector nozzle and two solenoids in a single body. combustion temperature exceeds 1372°C
Actuated by the camshaft via rocker arms with (2,500°F), oxygen and nitrogen combine in large
roller followers, electronic unit injectors offer quantities to form NOx. By themselves, NOx
precise fuel metering using a process called “rate emissions are no great hazard; however, when
shaping.” mixed with the right amount of HC in the air, NOx
will combine in the presence of sunlight to form
Engine Electronic Control Unit (EECU) smog.
A microprocessor-based controller usually
mounted on the cylinder block. On the MP8 Poly-V Belt
engine, a cooling plate mounts on the surface of A multi-ribbed belt design incorporated into the
the module. A tube on the plate conducts fuel accessory drive belt and pulley arrangement at
drawn from the tank on its way to the pump the front of the engine.
before being pressurized. The fuel acts as the
coolant. With the MACK V-MAC® IV system, the
EECU controls fuel timing and delivery, exhaust
gas recirculation, fan operation, engine protection
functions and engine brake operation.
Page 40
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TROUBLESHOOTING
ENGINE SYMPTOM DIAGNOSIS Before Troubleshooting Begins
[200 EA] Before troubleshooting begins, observe all shop
safety procedures.
The Vehicle Management and Control (V-MAC
IV) system monitors engine function and displays
a code when a fault is detected. The code can be Noise and Vibration
observed on the instrument panel or through an
electronic diagnostic tool. An explanation of the
NORMAL VERSUS ABNORMAL
fault codes can be found in VCADS, Guided
Diagnostics or the Fault Code Manual, 8-218. Noise is the name we give to vibration that
Guided Diagnostics also includes irritates us through our ears. Vibration can be felt
symptom-based troubleshooting. To obtain Tech without being heard. Engine operation can cause
Tool, contact your local MACK dealer. vibration and noise throughout a vehicle that we
regard as “normal.”
The Tech Tool provides complete system
diagnostics. For more information, see manual Abnormal noises and vibrations suggest that
8-371 or the Tech Tool web site. Repair something is not working properly or is not
information is available in the respective engine assembled properly. A damaged driveshaft can
service manuals and from the MACK Electronic cause abnormal vibration. A loose fastener allows
Information System (EIS). EIS is easily accessed two surfaces to rub or slap together causing
with Tech Tool. unusual noise in response to the vibration.
Be sure to discuss noise and vibration issues with
Troubleshooting Technique the driver. It is important to discover under what
conditions these occur. Maybe a test drive will be
Talk to the vehicle operator. Learn how the engine necessary to familiarize yourself with the details
operated before it failed. Ask about the of the driver's story. Even so, it will probably be
maintenance schedule and the fuel, coolant and necessary to start the diagnostic process with a
lubricant used. Begin by attempting to determine guess as to the nature of the difficulty.
whether anything has happened recently that
could point to the electrical system, but which is
not related to the electronic control system.
Depending on the vehicle configuration, a
problem may be caused, or influenced, by
malfunctions in other vehicle components. Be
sure to inspect for unusual conditions among the
batteries, tires, axles, trailer, bodybuilder
adaptations and other possibilities. Consult
specific service information resources according
to the conditions observed. Fuel waxing, for
example, can cause symptoms easily mistaken
for other engine problems.
If possible, recreate the problem in an
environment similar to that described by the
vehicle operator. Run the engine at the
temperature at which the symptom occurred.
Engine problems can be electrical, mechanical or
a combination of the two. Electrical and electronic
problems will, for the most part, cause fault codes
to be set in the V-MAC system.
Page 50
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TROUBLESHOOTING
If a large enough container cannot be obtained, If the cooler is being tested without being
the EGR cooler can be tested without being immersed in water, look inside the gas inlet port.
immersed in water by using the test plugs If bubbles are seen, the cooler is leaking
included with the kit, 88800216-5, to seal the gas internally and must be replaced.
outlet port. The EGR cooler core can then be
filled with water and tested by applying air
pressure to the coolant outlet port as shown in
Figure 54. When using this technique, the cooler
must be tested in the upright position. A stream of bubbles seen coming from around
the plugs in either of the coolant ports indicates
To ease the installation of the test plug, coat that the O-rings may be damaged. If this is the
the inside of the hose with a suitable O-ring case, remove the plugs, inspect the O-rings and
lubricant. replace as required.
54
6. Lift the EGR cooler out of the container and
remove the pressure testing equipment.
7. Dump the water from inside the EGR cooler
and then use compressed air to remove any
remaining water from the cooler core and
outer cover.
Engine Compression, Test
(on Vehicle)
Verify suspected leaks in the cylinder head or
block by pressure testing before replacing these.
Do not use Magnaflux® inspections alone as
replacement criteria.
Before proceeding with the tests, look for coolant
stains around the sealing plugs on the cylinder
head. Check that the plugs are installed properly
Figure 54 — Test with EGR Gas Outlet Port Plugged
and in good condition.
1. Test Plug, 88800216-5 2. EGR Cooler 1. Remove the cylinder head (valve) cover.
5. Apply air pressure (240 kPa [35 psi]) to the
EGR cooler. Maintain the pressure for
15 minutes. If the EGR cooler is leaking On engines fitted with PowerLeash™, secure the
internally, there will be a steady stream of pistons in the rocker arms with rubber bands or
bubbles coming from the gas inlet or outlet tie straps so the pistons do not drop out when the
openings. If a steady stream of bubbles rocker assembly is lifted. Pistons and rockers are
appears, replace the EGR cooler. matched together. Failure to heed this caution
may result in severe component damage.
Page 60
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MAINTENANCE
LUBRICATION SYSTEM MAINTENANCE
Special Tool
Tool No. Description Image
9998487 Oil Filter Wrench (Available)
Oil Level Check For accurate oil level readings, the dipstick must
be inserted fully into the dipstick tube. The level
When checking oil levels, the vehicle must be must be close to the FULL line (at least between
parked on level ground. Components must be the LOW and FULL lines) on the dipstick, but
filled to the correct level. DO NOT OVERFILL. must NOT exceed the FULL line.
72
The best time to check oil level is while the engine
is COLD (prior to starting at the beginning of the
work day, or after the vehicle has sat
approximately 2 hours). At normal operating
temperature (engine oil temperature above 80°C
[175°F]), oil level can be checked 15 minutes
after shut down.
Failure to wait a sufficient amount of time (2 hours
if engine oil temperature is below 80°C [175°F])
or 15 minutes if oil temperature is above 80°C
[175°F]) will result in an inaccurate dipstick Figure 72 — Oil Level Check
reading.
Page 70
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REPAIR INSTRUCTIONS, PART 1
16. If equipped, remove the exhaust bracket
from the flywheel housing.
The fan assembly is heavy and difficult to handle.
Obtain assistance to support it safely during
removal.
Use a container to collect power steering fluid.
15. Remove the fan assembly.
17. Remove the power steering hoses.
18. Disconnect the exhaust system from the
turbocharger.
If equipped with an electronically-controlled 19. Disconnect electrical cables or wires
viscous fan, store the fan assembly face down connected to the starter.
(hub flange up) or vertically as shown to prevent
fluid leaking from the assembly. 20. Disconnect or remove all other items
attached to the frame or cab that would
76
prevent engine removal, such as:
a. Clutch linkage
b. Ground straps
c. Electrical wiring
d. Coolant tubing
e. Air lines
f. Fuel lines
g. Hydraulic hoses or tubing
21. Remove the valve cover.
Cover the valve mechanism and gear train with a
suitable c\loth or similar covering to prevent dirt
and debris from entering the engine.
Figure 76 — Viscous Fan Drive Assembly Storage
1. OK to Store with Fan 2. OK to Store with Fan Use a transmission jack to support the
Blade in Vertical Position. Blade in Horizontal transmission when disconnected from the engine.
Position and Mounting
Flange Up. Do Not Store
with Mounting Flange
Down.
Page 80
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REPAIR INSTRUCTIONS, PART 1
Timing Gear Cover Removal
88
[211 AA]
1. Disconnect the oil supply line at the EGR
valve and at the flywheel housing. Remove
the line from the engine.
90
Figure 88 — Disconnecting Harness at Unit Injector
6. If so equipped, disconnect the harness from
the engine brake control valve.
89
Figure 90 — EGR Valve Oil Supply Line
2. Remove the mounting fastener and remove
the camshaft position sensor from the timing
gear cover.
Figure 89 — Engine Brake Control Valve Terminal
3. Remove all straps, P-clamps and other
retainers used to restrain harnesses, oil
7. Cut the cable ties holding the harness to the
lines and coolant tubes to the rear of the
cylinder head and the engine brake control
engine. This will allow the support bracket at
valve.
the rear of the engine to be removed.
8. Carefully pull the harness through the hole
at the front of the cylinder head and remove
the harness from the engine.
Page 90
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REPAIR INSTRUCTIONS, PART 1
11. Repeat the process to remove the remaining
unit injectors.
앫 If an injector nozzle gasket (flat washer) had
been used for the seal joint between the Starter Removal
injector copper sleeve and the injector,
discard the used gasket immediately after [272 DH]
the injector is removed. A used gasket must
not be reused. When the injector is The starter is held in place by nuts assembled
removed, this gasket may come out attached over studs installed at the front right side of the
to the injector or it may remain in the bottom flywheel housing.
of the injector sleeve.
앫 If the nozzle gasket (flat washer) is attached
to the injector, loosen it with gentle prying
from a thin flat gasket scrapper blade. If the The starter is heavy. Do NOT attempt to
gasket is in the bottom of the injector sleeve, remove the starter without the help of an
initially attempt to remove it with a magnet. If assistant or the use of a suitable lifting
this is unsuccessful, use a standard flat device. Failure to heed this warning may
blade screwdriver with a long thin shank and result in personal injury and component
narrow width blade to loosen the gasket. damage.
Locate the blade in the recess between the
outside of the gasket and the injector sleeve. 1. If not already done, disconnect the wiring
Use the blade to apply force on the outside harness from the starter motor.
of the gasket at different locations around
the gasket. Continue this until the gasket 2. Loosen the nuts fastening the starter to the
separates from the sleeve. flywheel housing.
115
10. If the injector is not being installed
immediately, install the protective plug into
the unit injector bore of the cylinder head to
protect it from debris.
114
Figure 115 — Starter
1. Flywheel Housing 2. Attaching Nuts
3. With the help of an assistant or a lifting
device, remove the starter from the engine.
Figure 114 — Installing Injector Bore Protective Plug
Page 100
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REPAIR INSTRUCTIONS, PART 1
EGR Mixer Removal
147
[214 HL]
1. If not already done, remove the fasteners
and remove the inlet pipe (elbow) from the
EGR mixer.
148
Figure 147 — Fan Hub and Accessory Drive System
Figure 148 — EGR Mixer Inlet Pipe
1. Fan Drive Belt 4. Accessory Drive Belt
2. Fan Hub Bracket 5. Fan Drive and Coolant 2. Remove the fasteners and EGR mixer
3. Accessory Drive Belt Pump Belt Tensioner (including fan ring support bracket) and
Tensioner gasket from the spacer block or inlet air
preheater, if so equipped.
149
4. Remove the fasteners and fan hub bracket
assembly.
Figure 149 — EGR Mixer Fasteners
3. Remove the spacer block from the inlet air
manifold. Or, if so equipped, remove all
power and ground cables from the inlet air
preheater and remove the preheater from
the manifold.
Page 110
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REPAIR INSTRUCTIONS, PART 1
Alternator and Refrigerant 3. If necessary, remove the fasteners and
remove the belt tensioner from the upper
Compressor Removal mounting bracket.
[271 CB, 264 DP] 4. Remove the fasteners and remove the upper
mounting bracket from the cylinder block.
172
It is not necessary to remove the front engine
support mounting bracket unless it is damaged
and in need of replacement.
Thermostat and Cover Removal
173
Figure 172 — Alternator and Refrigerant Compressor
Mounting
1. Fan Belt 4. Alternator
2. Tensioner 5. Refrigerant Compressor
3. Alternator Mounting 6. Front Engine Support Figure 173 — Thermostat and Cover
Bracket Mounting Bracket
1. Cylinder Head 3. Thermostat
2. Sealing Ring 4. Thermostat Cover
1. Remove the fasteners, thermostat cover,
For this procedure, the engine is out-of-chassis, thermostat and sealing ring.
the fan drive and accessory drive belts are
2. Carefully clean the thermostat seat and all
removed, the alternator harness wiring is
cylinder head-to-thermostat cover mating
disconnected, and the A/C compressor
surfaces.
refrigerant lines are removed.
1. While supporting the alternator, remove the
fasteners and remove the alternator from the
upper mounting bracket.
2. While supporting the refrigerant compressor,
remove the fasteners and remove the
compressor from its mounting pads on the
front engine support mounting bracket.
Page 120
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REPAIR INSTRUCTIONS, PART 1
CYLINDER BLOCK RECONDITIONING
[211 DB]
Tools and Equipment
SPECIAL TOOLS
Tool No. Description Images
9992000 Handle with Various Uses (fits 25 mm/1
inch hole) (Essential)
9996599 Liner Installation Plate (Available)
9996966 Liner Hold-Down Tool (Essential)
PT-6435 or Cylinder Liner Puller (Available)
PT-6400-C Note: Alternate tools for liner removal —
9992955, 9996394, 9996395 and 9996645
in combination.
Page 130
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REPAIR INSTRUCTIONS, PART 1
3. Using a generous amount of clean engine oil Used connecting rod screws must be lightly oiled
on the wrist pin and rod bearing, press the on the threads and under the head. New screws
wrist pin into the bore. are coated with phosphate and oil and must be
assembled dry.
4. Insert a snap ring in the other wrist pin
retaining groove.
5. Set the assembled piston aside in a clean
location until it is needed. If the capscrews are incorrectly assembled or
6. Repeat steps 1 through 5 for each piston. tightened to an incorrect torque, the assembly
must be discarded. Failure to heed this caution
may result in severe component damage.
Connecting rod capscrews can only be re-used