Cadillac 60 Series 1963 Shop Manual page 273

11-2
ENGINE COOLING
SERVICE INFORMATION
1. Radiator Filler Cap Removal
The radiator cap on all 1963 Cadillac cars is
of the bayonet type with a safety catch. To re-
move, place a cloth over the cap and rotate it
counterclockwise until the stop is reached. In
this position, the cooling system is vented to the
atmosphere through the overflow hose. The cap
should be left in this safety position until all pres-
sure or steam has been relieved.
If the coolant boils when the cap is placed in
the safety position and steam continues to escape,
cool the radiator by flowing cold water over the
outside while the engine is idling. The cap may
then be removed by pressing down slightly and
rotating cap further counterclockwise.
2. Cooling System Preventive
Maintenance
The cooling system should be drained, flushed
with water only, and refilled annually with water
and an ethylene glycol base anti-freeze to protect
the engine to at least -20°F. Inhibitor and sealer
should also be added to the system to retard rust
and scale, keep water passages open, seal against
internal leakage, and to assist in lubricating the
water pump.
Retorquing the cylinder head screws, checking
all hose connections, and adding inhibitor and
sealer should be performed annually, or when-
ever ethylene glycol base anti-freeze is changed.
The cylinder head screws should be torqued to
75 foot-pounds.
These maintenance procedures are necessary
to avoid the possibility of external leakage, and
of anti-freeze solutions leaking into the engine,
or combustion gases blowing into the cooling sys-
tem. Anti-freeze and water mixed with engine oil
will form sludge, which will interfere with lubri-
cation and, in some cases, may form varnish-like
deposits that will cause gumming and sticking of
moving parts.
Check coolant level at each engine oil change.
Maintain coolant level 1/2 inch to 1 inch above
cooling tubes in top of upper radiator tank when
the coolant is cold.
3. Testing Anti-Freeze Solutions
A hydrometer test will indicate whether anti-
freeze or water, or both, should be added to bring
the coolant to its proper level and to maintain the
desired freezing point of the solution.
Some devices used for testing anti-freeze solu-
tions will indicate the correct freezing point only
when tested at a specific temperature. Other
testers, provided with thermometers and tables,
indicate freezing points corresponding to readings
made at various temperatures. Disregarding the
temperature of the solution when testing may
cause an error as large as 30°F in determining
the freezing point.
4. Radiator and Cap Leak Check
The cooling system pressure should be checked
whenever cases of overheating, coolant loss, or
anti-freeze odors are reported. Any one of the
common types of cooling system testers will
prove helpful in testing the cooling system ac-
cording to the following procedure:
a. Testing Radiator Cap
CAUTION: Avoid removing the radiator cap
while the engine is at normal operating temper-
ature, as hot: coolant will spray out. If it is
necessary to remove the cap while the engine
is hot, rotate the cap slowly counterclockwise
until the first stop is reached, and allow pres-
sure to escape. Then turn it further counter-
clockwise to remove.
1. Remove radiator cap.
2. Wet cap gasket with water and wash
sediment, if any, then install cap on tester.
away
3. Build up pressure to cap capacity. The tester
should read within 13-1/2 to 16-1/2 psi for all
series cars.
4. The cap should hold the pressure within these
limits for approximately 10 seconds. A cap that
does not meet: these requirements should be
replaced.
b. Testing Cooling System
1. Tighten all cylinder head screws to 75 foot-
pounds.
2. Tighten all hose connections.
3. Fill radiator to normal level.
4. Install tester in radiator neck, following in-
structions supplied with tester.
5. Build pressure up to 15 psi.
6. Watch the gage for any drop in pressure.
A pressure drop will indicate a leak.
A pressure tester can also be used effectively
to test for leaks after components of the cooling
system have been serviced or replaced.