| |
TM 10-3930-653 14&P
Condition
Probable cause
Corrective action
Faulty radiator filler cap
Replace
Air in cooling system
Retighten each part of cooling system.
Improper engine oil grade
Replace with proper grade oil
Incorrect Ignition timing
Adjust
Faulty carburetor (lean mixture)
Overhaul carburetor.
Overcooling
Damaged thermostat
Replace
FUEL GRADE
Improper octane fuel
Replace with specified octane fuel.
BRAKE SYSTEM
Dragging brake
Adjust
NOISY ENGINE
Knocking
Carbon knocking
Disassemble cylinder head and remove
carbon
Timing knocking
Adjust ignition timing
Fuel knocking
Use specified octane fuel.
Preignition (misusing of spark plug)
Use specified spark plug.
Mechanical knocking
Crankshaft bearing
This strong dull noise increases when engine
This may cause an abnormal wearing of
knocking
is accelerated To locate the possible origin,
cylinder and lower compression which in
cause a misfire on each cylinder. If the noise
turn will cause lower out-put power and
stops by the misfire. this cylinder generates
excessive consumption of oil
the noise.
Connecting rod
This is a little higher-pitched noise than the
Same as the case of crankshaft bearings.
bearing knocking
crankshaft knocking, and also increases
when engine is accelerated Cause a misfire
on each cylinder and if the noise diminishes
almost completely, thus crankshaft bearing
generates the noise
Piston and cylinder
When you hear an overlapping metalic noise
This may cause an abnormal wearing of
noise
which increases its magnitude with the
cylinder and lower compression which in
revolution of engine and which decreases as
turn will cause a lower out-put power and
engine Is warmed up, this noise is caused by
excessive consumption of oil.
piston and cylinder To locate the place,
cause a misfire on each cylinder
Overhaul engine,
Piston pin noise.
This noise is heard at each highest and
This may cause a wear on piston pin, or
lowest dead end of piston To locate the
piston pin hole
place, cause a misfire on each cylinder
Renew piston and piston pin assembly.
Water pump noise
This noise may be caused by worn or
Replace water pump with a new one
damaged bearings, or by the uneven surface
of sliding parts
4 - 5
|