TM 5-3895-359-14&P
sealed with synthetic rubber seal rings which fit into
counterbored holes in the block. A synthetic rubber seal
fits into a milled groove near the perimeter of the block.
When the cylinder head is drawn down, a positive
leakproof metal-to-metal contact is assured between the
head and the block.
NOTE: Production non-turbocharged
cylinder heads include cast steel
exhaust valve seat inserts which have
magnetic qualities. An easy method for
determining the type of exhaust valve
seat insert in a cylinder head is with a
magnet. The magnet will be attracted
to the non-turbo insert (will stick). The
magnet will not be attracted to the turbo
insert, it will jump to the cylinder head.
Cylinder Head Maintenance
The engine operating temperature should be maintained
between 160-185 (71-85 ) and the cooling system
F
C
should be inspected daily and kept full at all times. The
cylinder head fire deck will overheat and crack in a short
time if the coolant does not cover the fire deck surface.
When necessary, add coolant slowly to a hot engine to
avoid rapid cooling which can result in distortion and
cracking of the cylinder head (and cylinder block).
Fig. 4. Water Nozzle in Two-Valve Cylinder Head
Abnormal operating conditions or neglect of certain
Other conditions which may eventually result in cylinder
maintenance items may cause cracks to develop in the
head cracks are:
cylinder head. If this type of failure occurs, a careful
inspection should be made to find the cause and avoid a
1. Excess fuel in the cylinders caused by leaking
recurrence of the failure.
injectors.
Unsuitable water in the cooling system may result in
2. Slipping fan belts can cause overheating by reducing
lime and scale formation and prevent proper cooling.
air flow through the radiator.
The cylinder head should be inspected around the
exhaust valve water jackets. This can be done by
3. Accumulation of dirt on the radiator core which will
removing an injector tube. Where inspection discloses
reduce the flow of air and slow the transfer of heat from
such deposits, use a reliable non-corrosive scale
the coolant to the air.
remover to remove the deposits from the cooling system
of the engine, since a similar condition will exist in the
4. Inoperative radiator cap which will result in loss of
cylinder block and other components of the engine.
coolant.
Refer to Page 10-9-13 for engine coolant
recommendations.
Remove Cylinder Head
Loose or improperly seated injector tubes may result in
Certain service operations on the engine require
compression leaks into the cooling system and also
removal of the cylinder head:
result in loss of engine coolant. The tubes must be tight
to be properly seated. Refer to Page 10-3-25.
1. Remove and install pistons.
Overtightened injector clamp bolts may also cause head
2. Remove and install cylinder liners.
cracks. Always use a torque wrench to tighten the bolts
to the specified torque.
10-2-20
