Dodge Ram Truck 1500-2500-3500. Manual — part 1311

DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE

The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions.

Ensure the battery is completely charged and the engine starter motor is in good operating condition. Otherwise the
indicated compression pressures may not be valid for diagnosis purposes.

1. Clean the spark plug recesses with compressed air.

2. Remove the spark plugs.

3. Disable the fuel system (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - DESCRIPTION).

4. Remove the ASD relay (Refer to 8 - ELECTRICAL/IGNITION CONTROL/AUTO SHUT DOWN RELAY -

REMOVAL).

5. Insert a compression pressure gauge and rotate the engine with the engine starter motor for three revolutions.

6. Record the compression pressure on the 3rd revolution. Continue the test for the remaining cylinders.

7.

(Refer to 9 - ENGINE - SPECIFICATIONS) for the correct engine compression pressures.

DIAGNOSIS AND TESTING - CYLINDER COMBUSTION PRESSURE LEAKAGE

The combustion pressure leakage test provides an accurate means for determining engine condition.

Combustion pressure leakage testing will detect:

•

Exhaust and intake valve leaks (improper seating).

•

Leaks between adjacent cylinders or into water jacket.

•

Any causes for combustion/compression pressure loss.

1. Check the coolant level and fill as required. DO NOT install the radiator cap.

2. Start and operate the engine until it attains normal operating temperature, then turn the engine OFF.

3. Remove the spark plugs.

4. Remove the oil filler cap.

5. Remove the air cleaner hose.

6. 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 and 552 kPa (80 psi) recommended.

7. Perform the test procedures on each cylinder according to the tester manufacturer’s instructions. Set piston of

cylinder to be tested at TDC compression,While testing, listen for pressurized air escaping through the throttle
body, tailpipe and oil filler cap opening. Check for bubbles in the radiator coolant.

All gauge pressure indications should be equal, with no more than 25% leakage.

FOR EXAMPLE: At 552 kPa (80 psi) input pressure, a minimum of 414 kPa (60 psi) should be maintained in the
cylinder.

Refer to CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART .

CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART

CONDITION

POSSIBLE CAUSE

CORRECTION

AIR ESCAPES THROUGH THROTTLE
BODY

Intake valve bent, burnt, or not seated
properly

Inspect valve and valve seat. Reface or
replace, as necessary. Inspect valve
springs. Replace as necessary.

AIR ESCAPES THROUGH TAILPIPE

Exhaust valve bent, burnt, or not seated
properly

Inspect valve and valve seat. Reface or
replace, as necessary. Inspect valve
springs. Replace as necessary.

AIR ESCAPES THROUGH RADIATOR

Head gasket leaking or cracked cylinder
head or block

Remove cylinder head and inspect.
Replace defective part

MORE THAN 50% LEAKAGE FROM
ADJACENT CYLINDERS

Head gasket leaking or crack in cylinder
head or block between adjacent
cylinders

Remove cylinder head and inspect.
Replace gasket, head, or block as
necessary

MORE THAN 25% LEAKAGE AND AIR
ESCAPES THROUGH OIL FILLER CAP
OPENING ONLY

Stuck or broken piston rings; cracked
piston; worn rings and/or cylinder wall

Inspect for broken rings or piston.
Measure ring gap and cylinder diameter,
taper and out-of-round. Replace
defective part as necessary

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ENGINE - 4.7L - SERVICE INFORMATION

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DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - INTRODUCTION

Engine diagnosis is helpful in determining the causes of malfunctions not detected and remedied by routine main-
tenance.

These malfunctions may be classified as either performance (e.g., engine idles rough and stalls) or mechanical
(e.g., a strange noise).

(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING) - PERFORMANCE and (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)—MECHANICAL for possible causes and corrections of malfunctions. (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY - DIAGNOSIS AND TESTING) and (Refer to 14 - FUEL SYSTEM/FUEL INJECTION - DIAGNO-
SIS AND TESTING) for the fuel system diagnosis.

Additional tests and diagnostic procedures may be necessary for specific engine malfunctions that can not be iso-
lated with the Service Diagnosis charts. Information concerning additional tests and diagnosis is provided within the
following diagnosis:

•

Cylinder Compression Pressure Test (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

•

Cylinder Combustion Pressure Leakage Test (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

•

Engine Cylinder Head Gasket Failure Diagnosis (Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNOSIS AND
TESTING).

•

Intake Manifold Leakage Diagnosis (Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD - DIAGNOSIS
AND TESTING).

STANDARD PROCEDURE

STANDARD PROCEDURE - REPAIR DAMAGED OR WORN THREADS

CAUTION: Be sure that the tapped holes maintain the original center line.

Damaged or worn threads can be repaired. Essentially, this repair consists of:

•

Drilling out worn or damaged threads.

•

Tapping the hole with a special Heli-Coil Tap, or equivalent.

•

Installing an insert into the tapped hole to bring the hole back to its original thread size.

STANDARD PROCEDURE - FORM-IN-PLACE GASKETS AND SEALERS

There are numerous places where form-in-place gaskets are used on the engine. Care must be taken when apply-
ing form-in-place gaskets to assure obtaining the desired results. Do not use form-in-place gasket material
unless specified. Bead size, continuity, and location are of great importance. Too thin a bead can result in leakage
while too much can result in spill-over which can break off and obstruct fluid feed lines. A continuous bead of the
proper width is essential to obtain a leak-free gasket.

There are numerous types of form-in-place gasket materials that are used in the engine area. Mopar

T

Engine RTV

GEN II, Mopar

T

ATF-RTV, and Mopar

T

Gasket Maker gasket materials, each have different properties and can not

be used in place of the other.

MOPAR

T

ENGINE RTV GEN II

Mopar

T

Engine RTV GEN II is used to seal components exposed to engine oil. This material is a specially designed

black silicone rubber RTV that retains adhesion and sealing properties when exposed to engine oil. Moisture in the
air causes the material to cure. This material is available in three ounce tubes and has a shelf life of one year. After
one year this material will not properly cure. Always inspect the package for the expiration date before use.

MOPAR

T

ATF RTV

Mopar

T

ATF RTV is a specifically designed black silicone rubber RTV that retains adhesion and sealing properties

to seal components exposed to automatic transmission fluid, engine coolants, and moisture. This material is avail-
able in three ounce tubes and has a shelf life of one year. After one year this material will not properly cure. Always
inspect the package for the expiration date before use.

MOPAR

T

GASKET MAKER

Mopar

T

Gasket Maker is an anaerobic type gasket material. The material cures in the absence of air when

squeezed between two metallic surfaces. It will not cure if left in the uncovered tube. The anaerobic material is for
use between two machined surfaces. Do not use on flexible metal flanges.

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ENGINE - 4.7L - SERVICE INFORMATION

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MOPAR

T

GASKET SEALANT

Mopar

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Gasket Sealant is a slow drying, permanently soft sealer. This material is recommended for sealing

threaded fittings and gaskets against leakage of oil and coolant. Can be used on threaded and machined parts
under all temperatures. This material is used on engines with multi-layer steel (MLS) cylinder head gaskets. This
material also will prevent corrosion. Mopar

T

Gasket Sealant is available in a 13 oz. aerosol can or 4oz./16 oz. can

w/applicator.

FORM-IN-PLACE GASKET AND SEALER APPLICATION

Assembling parts using a form-in-place gasket requires care but it’s easier than using precut gaskets.

Mopar

T

Gasket Maker material should be applied sparingly 1 mm (0.040 in.) diameter or less of sealant to one

gasket surface. Be certain the material surrounds each mounting hole. Excess material can easily be wiped off.
Components should be torqued in place within 15 minutes. The use of a locating dowel is recommended during
assembly to prevent smearing material off the location.

Mopar

T

Engine RTV GEN II or ATF RTV gasket material should be applied in a continuous bead approximately 3

mm (0.120 in.) in diameter. All mounting holes must be circled. For corner sealing, a 3.17 or 6.35 mm (1/8 or 1/4 in.)
drop is placed in the center of the gasket contact area. Uncured sealant may be removed with a shop towel. Com-
ponents should be torqued in place while the sealant is still wet to the touch (within 10 minutes). The usage of a
locating dowel is recommended during assembly to prevent smearing material off the location.

Mopar

T

Gasket Sealant in an aerosol can should be applied using a thin, even coat sprayed completely over both

surfaces to be joined, and both sides of a gasket. Then proceed with assembly. Material in a can w/applicator can
be brushed on evenly over the sealing surfaces. Material in an aerosol can should be used on engines with multi-
layer steel gaskets.

REMOVAL

NOTE: This procedure applies to both the 4X2 and 4X4 vehicles, steps that apply to the 4X4 vehicle only,
are identified.

1. Release fuel rail pressure (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - STANDARD PROCEDURE) then

disconnect the fuel supply quick connect fitting at the fuel rail (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCEDURE).

2. Disconnect the battery negative and positive cables.

3. Raise vehicle on hoist.

4. Remove exhaust crossover pipe from exhaust manifolds.

5. 4X4 vehicles Disconnect axle vent tube from left side engine mount.

6. Remove the through bolt retaining nut and bolt from both the left and right side engine mounts.

7. 4X4 vehicles Remove locknut from left and right side engine mount brackets.

8. Disconnect two ground straps from the lower left hand side and one ground strap from the lower right hand side

of the engine.

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ENGINE - 4.7L - SERVICE INFORMATION

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9. Disconnect crankshaft position sensor (1).

NOTE: The following step applies to 4X4 vehicles equipped with automatic transmission only.

10. 4X4 vehicles Remove the axle isolator bracket from the engine, transmission and the axle.

11. Remove structural cover (Refer to 9 - ENGINE/

ENGINE

BLOCK/STRUCTURAL

COVER

-

REMOVAL).

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ENGINE - 4.7L - SERVICE INFORMATION

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