Valve Stem Seal; Intake Manifold; Exhaust Manifold; Diagnosis And Testing - Jeep cherokee 2000 Service Manual

9 - 8 2.5L ENGINE
DESCRIPTION AND OPERATION (Continued)

VALVE STEM SEAL

DESCRIPTION
The valve stem seals are made of rubber and incor-
porate a garter spring to maintain consistent lubrica-
tion control (Fig. 9).

INTAKE MANIFOLD

DESCRIPTION
The intake manifold is made of cast aluminum and
uses seven bolts to mount to the cylinder head. This
mounting style improves sealing and reduces the
chance of leaks.
Fig. 12 Intake and Exhaust Manifold

EXHAUST MANIFOLD

DESCRIPTION
The exhaust manifold is log style and is made of
high silicon molybdenum cast iron. The exhaust man-
ifold shares a common gasket with the intake mani-
fold. The exhaust manifold also incorporates a ball
flange outlet for improved sealing and strain free
connections (Fig. 12).

DIAGNOSIS AND TESTING

ENGINE DIAGNOSIS—INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
Refer to the Service Diagnosis—Performance chart
and the Service Diagnosis—Mechanical chart for pos-
sible causes and corrections of malfunctions. Refer to
Group 14, Fuel System for the fuel system diagnosis.
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
• Cylinder Compression Pressure Test.
• Cylinder Combustion Pressure Leakage Test.
• Engine Cylinder Head Gasket Failure Diagnosis.
• Intake Manifold Leakage Diagnosis.
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