CYLINDER HEAD
DESCRIPTION
The cylinder head is constructed of cast iron and is a one piece cross flow design with four valves per cylinder. The
arrangement of two intake and two exhaust valves per cylinder allows for a centrally located injector. The cylinder
head also includes an integral intake manifold, an integral thermostat housing, and a longitudal fuel return rifle,
which exits at the rear of the head. The 24 valve design also includes integrally cast valve guides and hardened
intake and exhaust valve seat inserts.
REMOVAL
1. Disconnect battery negative cables.
2. Raise vehicle on hoist.
3. Drain engine coolant.
4. Disconnect exhaust pipe from turbocharger elbow.
5. Remove turbocharger drain tube bolts at turbocharger. Cap off ports to prevent dirt or foreign material from enter-
ing.
6. Lower vehicle.
7. Disconnect air inlet temperature/pressure sensor.
8. Remove air cleaner housing and snorkel from the vehicle. Cap off turbocharger air inlet to prevent intrusion of
dirt or foreign material.
9. Disconnect cab heater core supply and return hoses from the cylinder head and heater pipe.
10. Disconnect turbocharger oil supply line at the turbocharger end. Cap off open ports to prevent intrusion of dirt
or foreign material.
11. Remove exhaust manifold-to-cylinder head bolts, spacers, heat shield, retention straps, and cab heater plumb-
ing. Remove exhaust manifold and turbocharger from the vehicle as an assembly.
12. Remove cooling fan/drive/shroud assembly. (Refer to 7 - COOLING/ENGINE/RADIATOR FAN - REMOVAL)
13. Remove accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
14. Remove cooling fan support from cylinder block.
15. Remove upper generator bolt, loosen lower generator bolt, and rotate generator away from cylinder head.
16. Disconnect radiator upper hose from the thermostat housing.
17. Disconnect the Intake Air Temperature/Manifold Air Pressure, and Coolant Temperature sensor connectors.
18. Remove the engine harness to cylinder head attaching bolts and P-clipsat front of head.
19. Remove the intake air grid heater wires from the grid heater.
20. Remove engine oil level indicator tube attaching bolt at fuel filter housing bracket and inlet air connection..
21. Remove the charge air cooler-to-air inlet housing pipe.
22. Remove the engine wire harness attaching bolt and wire harness push-infastener from air inlet housing.
23. Remove the air inlet housing and intake grid heater from the intake manifold cover.
24. Remove the two grid heater harness-to-cylinder head attaching bolts at front of cylinder head.
NOTE: Extreme care should be used to keep dirt/debris from entering the fuel lines. Plastic caps should be
used on the ends of the fuel lines.
25.Remove the high pressure pump to fuel rail fuel line as follows:
a. Loosen fuel line nuts at fuel pump and at fuel rail.
b. Use a back-up wrench on the fitting at the fuel pump to keep it from loosening.
26. Remove the fuel rail to cylinder head fuel lines as follows:
a. Loosen No. 6 high pressure fuel line shield and position out of way.
b. Loosen the fuel line nuts at the fuel rail and at the cylinder head. Use a back-up wrench on HPC nut.
c. Remove the fuel line bracket bolts at the intake manifold cover.
OIL
STANDARD PROCEDURE
STANDARD PROCEDURE - ENGINE OIL LEVEL
CAUTION: Do not overfill crankcase with engine
oil, oil foaming and oil pressure loss can result.
To ensure proper lubrication of an engine, the engine
oil must be maintained at an acceptable level. The
acceptable oil level is in the SAFE RANGE (3) on the
engine oil dipstick.
1. Position vehicle on level surface.
2. With engine OFF, allow approximately 15 minutes
for oil to settle to bottom of crankcase, remove
engine oil dipstick.
3. Wipe dipstick clean.
4. Replace dipstick and verify it is seated in the tube.
5. Remove dipstick, with handle held above the tip, take oil level reading.
6. Add oil only if level is below the SAFE RANGE area on the dipstick.
7. Replace dipstick.
STANDARD PROCEDURE - ENGINE OIL SERVICE
WARNING: HOT OIL CAN CAUSE PERSONAL INJURY.
NOTE: Change engine oil and filter at intervals specified in the owner’s manual.
1. Operate the engine until the water temperature reaches 60°C (140°F). Shut the engine off.
2. Use a container that can hold at least 14 liters (15 quarts) to hold the used oil. Remove the oil drain plug and
drain the used engine oil into the container.
3. Always check the condition of the used oil. This can give you an indication of engine problems that might exist.
Thin, black oil indicates fuel dilution.
Milky discoloration indicates coolant dilution.
4. Clean the area around the oil filter head. Remove the filter (Refer to 9 - ENGINE/LUBRICATION/OIL FILTER -
REMOVAL).
5. Install new oil filter (Refer to 9 - ENGINE/LUBRICATION/OIL FILTER - INSTA L L AT I O N ) .
6. Clean the drain plug and the sealing surface of the pan. Check the condition of the threads and sealing surface
on the oil pan and drain plug.
7. Install the drain plug. Tighten the plug to 50 Nꞏm (37 ft. lbs.) torque.
8. Use only High-Quality Multi-Viscosity lubricating oil in the Cummins Turbo Diesel engine. Choose the correct oil
for the operating conditions (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION).
9. Fill the engine with the correct grade of new oil (Refer to LUBRICATION & MAINTENANCE/FLUID CAPACITIES
- SPECIFICATIONS).
10. Start the engine and operate it at idle for several minutes. Check for leaks at the filter and drain plug.
11. Stop engine. Wait 15 minutes to allow the oil to drain back to the pan and check the level again.
USED ENGINE OIL DISPOSAL
Care should be exercised when disposing of used engine oil after it has beendrained from a vehicle’s engine.
3. Clean spark plug recesses with compressed air.
4. Remove the spark plugs.
5. Remove the oil fill cap.
6. Remove the air cleaner.
7. Calibrate the tester according to the manufacturer’s instructions. The shop air source for testing should maintain
483 kPa (70 psi) minimum, 1,379 kPa (200 psi) maximum, with 552 kPa (80 psi) recommended.
8. Perform the test procedures on each cylinder according to the tester manufacturer’s instructions. While testing,
listen for pressurized air escaping through the throttle body, tailpipe and oil filler cap opening. Check for bubbles
in the coolant pressure bottle.
All gauge pressure indications should be equal, with no more than 25 percent leakage per cylinder.
FOR EXAMPLE:At 552 kPa (80 psi) input pressure, a minimum of 414 kPa (60 psi) should be maintained in the
cylinder.
CYLINDER HEAD GASKET FAILURE DIAGNOSIS
A cylinder head gasket leak can be located between adjacent cylinders, between a cylinder and the adjacent water
jacket, or an external coolant leak may be present.
Possible indications of the cylinder head gasket leaking between adjacent cylinders are:
Loss of engine power
Engine misfiring
Poor fuel economy
Possible indications of the cylinder head gasket leaking between a cylinder and an adjacent water jacket are:
Engine overheating
Loss of coolant
Excessive steam (white smoke) emitting from exhaust
Coolant foaming
CYLINDER-TO-CYLINDER LEAKAGE TEST
To determine if an engine cylinder head gasket is leaking between adjacentcylinders, follow the procedures in Cyl-
inder Compression Pressure Test in this section. An engine cylinder head gasket leaking between adjacent cylinders
will result in approximately a 50-70% reduction in compression pressure.Cylinders adjacent to each other will both
have low compression.
CYLINDER-TO-WATER JACKET LEAKAGE TEST
WARNING: Use extreme caution when the engine is operating with coolant pressure cap removed.
VISUAL TEST METHOD
With the engine cool, remove the coolant pressure cap. Start the engine andallow it to warm up until thermostat
opens.
If a large combustion/compression pressure leak exists, bubbles will be visible in the coolant.
COOLING SYSTEM TESTER METHOD
WARNING: With cooling system tester in place, pressure will build up fast.Excessive pressure built up, by
continuous engine operation, must be released to a safe pressure point. Never permit pressure to exceed
138 kpa (20 psi).
Install Cooling System Tester 7700 or equivalent to pressure cap neck. Start the engine and observe the tester’s
pressure gauge. If gauge pulsates with every power stroke of a cylinder a combustion pressure leak is evident.
5. Identify the fluid in the cylinder(s) (i.e., coolant, fuel, oil or other).
6. Make sure all fluid has been removed from the cylinders. Inspect engine for damage (i.e., connecting rods, pis-
tons, valves, etc.)
7. Repair engine or components as necessary to prevent this problem from re-occurring.
CAUTION: Squirt approximately one teaspoon of oil into the cylinders, rotateenginetolubricatethecylin-
der walls to prevent damage on restart.
8. Install new spark plugs.
9. Drain engine oil and remove oil filter.
10. Fill engine with specified amount of approved oil and install new oil filter.
11. Connect negative battery cable.
12. Start engine and check for any leaks.
REMOVAL - ENGINE ASSEMBLY
1. Perform fuel pressure release procedure (Refer to
14 - FUEL SYSTEM/FUEL DELIVERY - STAN-
DARD PROCEDURE).
2. Disconnect negative battery cable.
3. Disconnect throttle body air inlet duct, remove air
cleaner cover (Refer to 9 - ENGINE/AIR INTAKE
SYSTEM/AIR CLEANER ELEMENT - REMOVAL).
4. Raise and support the vehicle.
5. Remove the lower engine shield.
6. Drain cooling system (Refer to 7 - COOLING/EN-
GINE - STANDARD PROCEDURE - DRAINING
COOLING SYSTEM).
7. Paint mark and remove the driveshaft (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - REMOVAL).
8.Removethetransmission(Referto21-TRANS-
MISSION/TRANSAXLE/MANUAL - REMOVAL).
9. Remove the starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - REMOVAL).
10. Disconnect the front exhaust pipe flange to
exhaust manifold fasteners (1 and 2).
11. Disconnect the hydraulic cooling fan lines and capture any spillage (Refer to 7 - COOLING/ENGINE/RADIATOR
FA N - R E M O VA L ) .
12. Drain engine oil and remove the oil filter.
13. Separate the air conditioning hose from the fan shroud.
14. Disconnect the lower radiator hose.
15. Disconnect the power steering line support bracket at the lower left ofthe radiator.
16. Loosen both engine mount through bolts.
COVER-TIMING CHAIN
REMOVAL
1. Disconnect negative battery cable.
2. Disconnect throttle body air inlet duct at the throttle
body, CCV hose, disconnect the IAT sensor and
remove air cleaner housing cover (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM - REMOVAL).
3. Remove the oil indicator tube (1) fastener at the
right cylinder head cover.
4. Raise and support the vehicle.
5. Remove the lower engine shield.
6. Drain cooling system (Refer to 7 - COOLING/EN-
GINE - STANDARD PROCEDURE - DRAINING
COOLING SYSTEM).
7. Drain engine oil and remove oil filter (Refer to 9 -
ENGINE/LUBRICATION/OIL - STANDARD PRO-
CEDURE).
8. Drain power steering.
9. Disconnect the cooling fan return hose at radiator
fan.
10. Disconnect the radiator fan pressure hose to
power steering rack.
11. Disconnect the power steering hose to power steering pump.
12. Separate the A/C hose from the radiator fan module.
13. Remove the lower radiator hoses.
14. Remove the front frame cross member (Refer to 13 - FRAME & BUMPERS/FRAME/FRONT CROSSMEMBER
- REMOVAL).
15. Remove the flywheel inspection cover.
NOTE: Capture and properly dispose of any fuel spillage.
16. Disconnect oil cooler line at the timing cover using Special Tool 9005 (Refer to 9 - ENGINE/LUBRICATION/OIL
COOLER & LINES - STANDARD PROCEDURE).
17. Separate the oil cooler coolant hose from the timing cover.
OIL
STANDARD PROCEDURE
CHECKING ENGINE OIL LEVEL
The best time to check engine oil level is after the
vehicle has sat overnight. If the engine has been run-
ning, allow the engine to be shut off for at least 5 min-
utes before checking oil level.
Checking the oil while the vehicle is on level ground
will improve the accuracy of the oil level reading.
Remove the engine oil indicator. The indicator is cali-
brated for 1 quart within the SAFE zone.
ENGINE OIL AND FILTER CHANGE
WARNING: NEW OR USED ENGINE OIL CAN BE IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL. CONTAMINANTS IN USED ENGINE OIL, CAUSED BY INTER-
NAL COMBUSTION, CAN BE HAZARDOUS TO YOUR HEALTH. THOROUGHLY WASH EXPOSED SKIN WITH
SOAP AND WATER. DO NOT WASH SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR SOLVENTS,
HEALTH PROBLEMS CAN RESULT. DO NOT POLLUTE, DISPOSE OF USED ENGINE OIL PROPERLY. CON-
TACT YOUR DEALER OR GOVERNMENT AGENCY FOR LOCATION OF COLLECTION CENTER INYOUR
AREA.
Change engine oil and filter at mileage and time intervals described in LUBRICATION AND MAINTENANCE (Refer
to LUBRICATION & MAINTENANCE/MAINTENANCE SCHEDULES - DESCRIPTION).
ENGINE OIL AND FILTER CHANGE
1. Run engine until achieving normal operating temperature.
2. Position the vehicle on a level surface and turn engine off.
3. Open hood, remove oil fill cap.
4. Raise vehicle on hoist.
5. Remove underbody front shield
6. Place a suitable drain pan under oil pan drain plug.
7. Remove drain plug from oil pan and allow oil to drain into pan. Inspect drain plug threads for stretching or other
damage. Replace drain plug and gasket if damaged.
8. Install drain plug in crankcase.
9. Remove oil filter and replace with new.
10. Install under body shield.
11. Lower vehicle and fill crankcase with specified type (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES
- DESCRIPTION) and amount of engine oil (Refer to LUBRICATION & MAINTENANCE - SPECIFICATIONS).
CONVERTER-CATALYTIC
DESCRIPTION
WARNING: THE NORMAL OPERATING TEMPERATURE OF THE EXHAUST SYSTEM IS VERY HIGH. THERE-
FORE, NEVER WORK AROUND OR ATTEMPT TO SERVICE ANY PART OF THE EXHAUST SYSTEMUNTIL IT
IS COOLED. SPECIAL CARE SHOULD BE TAKEN WHEN WORKING NEAR THE CATALYTIC CONVERTER.
THE TEMPERATURE OF THE CONVERTER RISES TO A HIGH LEVEL AFTER A SHORT PERIOD OFENGINE
OPERATION TIME.
CAUTION: DO NOT remove spark plug wires from plugs or by any other means short out cylinders. Failure
of the catalytic converter can occur due to a temperature increase caused by unburned fuel passing
through the converter.
The stainless steel catalytic converter body is designed to last the life of the vehicle. Excessive heat can result in
bulging or other distortion, but excessive heat will not be the fault of theconverter. If unburned fuel enters the con-
verter, overheating may occur. If a converter is heat-damaged, correct the cause of the damage at the same time
the converter is replaced. Also, inspect all other components of the exhaust system for heat damage.
Unleaded gasoline must be used to avoid contaminating the catalyst core.
50 State emission vehicles incorporate two mini catalytic converters located after the exhaust manifolds and before
the inline catalytic converter.
OPERATION
The catalytic converter captures and burns any unburned fuel mixture exiting the combustion chambers during the
exhaust stroke of the engine. This process aids in reducing emissions output.
REMOVAL
3.7L/4.7L ENGINE
1. Raise and support vehicle.
2. Saturate the bolts and nuts with heat valve lubri-
cant. Allow 5 minutes for penetration.
3. Disconnect oxygen sensor electrical connectors.
4. Remove clamp (4).
5. Remove bolts exhaust to manifold (2).
6. Remove catalytic converter (3).
FUEL DELIVERY - GAS
DESCRIPTION
The fuel delivery system consists of:
a fuel pump module containing the electric fuel pump, fuel filter/fuel pressure regulator, fuel gauge sending unit
(fuel level sensor) and a secondary fuel filter located at the bottom of thepump module
fuel tubes/lines/hoses
a combination fuel filter/fuel pressure regulator
quick-connect fittings
fuel injector rail
fuel tank
fuel tank filler/vent tube assembly
fuel tank filler tube cap
accelerator pedal
throttle cable
Certain fuel delivery components can be found in the following graphics: