Repair Damaged Or Worn Threads; Service Engine Assembly (Short Block); Hydrostatic Lock; Engine Oil Service - Jeep cherokee 2000 Service Manual

9 - 88 4.0L ENGINE
SERVICE PROCEDURES (Continued)

REPAIR DAMAGED OR WORN THREADS

CAUTION: Be sure that the tapped holes maintain
the original center line.
Damaged or worn threads can be repaired. Essen-
tially, 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.

SERVICE ENGINE ASSEMBLY (SHORT BLOCK)

A service replacement engine assembly (short
block) may be installed whenever the original cylin-
der block is defective or damaged beyond repair. It
consists of the cylinder block, crankshaft, piston and
rod assemblies. If needed, the camshaft must be pro-
cured separately and installed before the engine is
installed in the vehicle.
A short block is identified with the letter "S"
stamped on the same machined surface where the
build date code is stamped for complete engine
assemblies.
Installation includes the transfer of components
from the defective or damaged original engine. Fol-
low the appropriate procedures for cleaning, inspec-
tion and torque tightening.

HYDROSTATIC LOCK

When an engine is suspected of hydrostatic lock
(regardless of what caused the problem), follow the
steps below.
(1) Perform the Fuel Pressure Release Procedure
(refer to Group 14, Fuel System).
(2) Disconnect the negative cable from the battery.
(3) Inspect air cleaner, induction system and
intake manifold to ensure system is dry and clear of
foreign material.
(4) Place a shop towel around the spark plugs to
catch any fluid that may possibly be under pressure
in the cylinder head. Remove the plugs from the
engine.
CAUTION: DO NOT use the starter motor to rotate
the crankshaft. Severe damage could occur.
(5) With all spark plugs removed, rotate the crank-
shaft using a breaker bar and socket.
(6) Identify the fluid in the cylinders (i.e. coolant,
fuel, oil, etc.).
(7) Make sure all fluid has been removed from the
cylinders.
(8) Repair engine or components as necessary to
prevent this problem from occurring again.
(9) Squirt engine oil into the cylinders to lubricate
the walls. This will prevent damage on restart.
(10) Install new spark plugs. Tighten the spark
plugs to 37 N·m (27 ft. lbs.) torque.
(11) Drain engine oil. Remove and discard the oil
filter.
(12) Install the drain plug. Tighten the plug to 34
N·m (25 ft. lbs.) torque.
(13) Install a new oil filter.
(14) Fill engine crankcase with the specified
amount and grade of oil (refer to Group 0, Lubrica-
tion and Maintenance).
(15) Connect the negative cable to the battery.
(16) Start the engine and check for any leaks.

ENGINE OIL SERVICE

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
INTERNAL 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.
ENGINE OIL SPECIFICATION
CAUTION: Do not use non-detergent or straight
mineral oil when adding or changing crankcase
lubricant. Engine failure can result.
API SERVICE GRADE CERTIFIED
Use an engine oil that is API Service Grade Certi-
fied. MOPAR provides engine oils that conform to the
latest recommended service grades.
Standard engine oil identification notations have
been adopted to aid in the proper selection of engine
oil. The identifying notations are located on the label
of engine oil plastic bottles and the top of engine oil
cans (Fig. 39).
Fig. 39 Engine Oil Container Standard Notations
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