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7-10
COOLING SYSTEM
(4) If the pressure gauge reading holds steady, the
system is satisfactory. If the pressure drops, continue
the
test
as follows:
(5)
Test all points for external leaks. If no external
leaks are found after the gauge dial showed a drop in
pressure, continue the
test.
(6)
Remove the tester and run the engine until nor-
mal operating temperature is reached.
(7) Re-attach the tester, apply 7 psi pressure and
increase engine speed to half throttle.
(8) If the needle on the dial fluctuates,
it
indicates
a combustion leak, generally at the head gasket. On
V-8 engines, detach spark plug leads from one bank
and operate the engine on the opposite bank. If the
needle continues to fluctuate, the bank in operation
leaks. If the needle stops fluctuating, the bank not in
operation leaks.
(9) If the needle on the dial did not fluctuate in
step 7, sharply accelerate the engine several times.
If an abnormal amount of water emits from the tail
pipe,
it
indicates a head gasket leak, cracked block,
or cracked head.
ENGINE WATER TEMPERATURE GAUGE
For Removal, Installation and Testing procedures of
the water temperature sending and receiving units,
refer to Group 8, Electrical system, "Gauges."
PROPER BELT TENSION
The satisfactory performance of the belt driven ac-
cessories depends on the maintenance of the proper
belt tension. If the specified tensions are not main-
tained, belt slippage may cause engine overheating,
lack of power steering assist, loss in air condition-
ing capacity, reduced alternator charging rates,
and greatly reduced belt life. To avoid any such ad-
verse effects, the following service procedure should
be followed:
(1) Retighten all belts to the specified
used belt
tension at the new vehicle preparation.
(2)
Retighten all belts at the
2
month service in-
spection.
(3)
Measure all belts by the deflection method at
servicing and retighten if needed.
(4) The new belt tension specifications should be
used
on
all belt replacements, and the above proce-
dure followed thereafter.
There are two methods by which belt tensions can
be properly established.
Belt Deflection Method
The belts may be adjusted by measuring the de-
flection of the belt at the mid-point between two pul-
leys under a five-pound push or pull. A small spring
scale can be used to establish the five-pound load.
See Figure 14 for correct locations at which to meas-
ure deflection.
This method should be used only when it is not pos-
sible to use the torque method, as it is a less accurate
substitute. To adjust the belts by the deflection meth-
od, loosen all the mounting bolts and use a bar to ap-
ply tension to the belts being careful not to damage
the accessory. Tighten the mounting bolts and meas-
ure the deflection. (See Belt Tension Specifications.)
It may be necessary to repeat this procedure several
times to establish the correct tension.
Any belt that has operated for a minimum
of
a
half-hour is considered to be "used."
Torque Method
The alternator and power steering pump belts may
be adjusted to the specified tension, by the use of a
torque wrench. (Refer to Belt Tension Specifications.)
The alternator belts are adjusted by using Tool C-3841
along with a torque wrench.
The power steering belts are adjusted by inserting
the square shank of the torque wrench into the hole
provided in the pump bracket.
To tighten the belts by the torque method, loosen
all the mounting bolts, then apply the specified torque
to the accessory, as shown in the Specifications. Tight-
en all the mounting bolts while the torque is applied
to the accessory.
Other belts may also be tightened by this method
if
the adjusting bracket has
a
square hole.
If
it is not
possible to use the torque wrench, because of clear-
ance, use an extension.
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