Buick LeSabre 1965 Service Manual page 49

ENGINE TROUBLE DIAGNOSIS 2 - 2 7
particularly at idling and low
speeds. A thorough engine tune-
care operation is the proper cor-
rection (par. 2-10).
b. Fan, Delcotron Generator
Belt, or Water Pump
Bent fan blades will cause vibra-
tion and noise. Fan blades may be
bent by accident or by the ob-
jectionable practice of turning the
engine by means of the blades.
Remove fan belt and run engine.
If vibration or noise is eliminated
or reduced it indicates that the
condition is caused by the fan,
generator, belt, or possibly the
water pump.
Check water pump for rough or
noisy bearing and replace parts
if necessary.
Inspect fan belt, all pulleys, bal-
ancer, fan blades, and Delcotron
generator for undercoating or
other material that would cause
an unbalanced condition. Examine
fan belt for abnormally thick or
thin sections.
Check fan blades for excessive
runout and correct if necessary.
Check all pulleys for abnormal
runout or wobble and replace if
necessary.
Reinstall fan belt and adjust to
proper tension. See Figures 2-49
thru 2-52.
With engine running, place one
hand on generator and slowly open
throttle from idle to approxi-
mately 60 MPH. If generator vib-
rates enough to create a noise in
the engine or car it will vibrate
enough to be felt by the hand. As
the engine is slowly speeded up
the generator might be felt to go
into periods of vibration at dif-
ferent engine s p e e d s . N o i s e
caused by the generator should
occur at the same time that gen-
erator vibration occurs. Repair
or replace a noisy generator.
If the generator is causing a moan
or whine it will increase in inten-
sity when car lights are turned on.
Replacement of generator is gen-
erally the only remedy for this
condition.
c. Engine Mountings
Vibration may be c a u s e d by
broken or deteriorated e n g i n e
mountings, or by mountings, or
by mountings that are loose or
improperly adjusted. Adjust and
t i g h t e n loose mountings (par.
2-26) or replace faulty mountings.
d. Crankshaft Balancer
Loose or broken rivets in the
crankshaft balancer may cause
vibration in the engine. If the
balancer is damaged by accident
in such manner that the parts
cannot function freely, extreme
roughness will be produced which
may eventually cause breakage of
the crankshaft if it is not cor-
rected. A balancer which shows
external evidence of damage or
which is suspected of being in-
operative should be replaced and
the result checked, since it is
not possible to test the balancer
in any other way.
e. Unbalanced Connecting
Rods or Pistons
Vibration will result if connecting
rods or pistons a r e installed
which are not of equal weight
with all other rods or pistons in
engine. If new parts have recently
been installed, these should be
c h e c k e d to determine whether
they are standard Buick parts or
have been a l t e r e d in weight
by filing, machining, or other
repairs.
f. Unbalanced Flywheel or
Converter Pump
Vibration may be due to unbal-
anced flywheel or the converter
pump. Procedure for balancing
these p a r t s is given in par-
agraph 2-28.
2 - 1 2 COOLING SYSTEM
TROUBLE DIAGNOSIS
a. Excessive Water Loss
If the radiator is filled too full
when cold, expansion when hot
will overfill t h e radiator and
coolant will be lost through the
overflow pipe. Adding unneces-
sary water will weaken the anti-
freeze solution and raise the
temperature at w h i c h freezing
may occur. To avoid losses from
this cause never f i l l radiator
beyond half way between core and
tank top.
If the cooling system requires
frequent addition of w a t e r in
order to maintain t h e proper
level in the radiator, check all
units and connections in the cool-
ing system for evidence of leak-
age. Inspection should be made
with cooling system cold because
small leaks w h i c h may show
dampness or dripping when cold
can easily escape detection when
the engine is hot, due to the rapid
evaporation of the leakage. Tell-
tale stains of grayish white or
rusty color, or dye stains from
anti-freeze, at joints in cooling
system are almost always sure
signs of small leaks even though
there appears to be no dampness.
Air or gas entrained in the cool-
ing system may raise the level
in radiator and cause loss of
coolant through the overflow pipe.
Air may be drawn into the cooling
system through leakage at the
water pump seal. Gas may be
forced into the cooling system
through leakage at the cylinder
head gasket even though the leak-
age is not sufficient to allow
water to enter the combustion
chamber. The following q u i c k