Cadillac 1967 VVI Data Book page 182

If gage continues to register above normal with coolant at
correct level, have your Authorized Cadillac Dealer make a
thorough check of the system.
Cooling system protection
The inhibited year-around (permanent-type) engine coolant
used to fill the cooling system at the factory, is a high quality
solution that meets General Motors Specification 1899-M. This
factory-fill coolant solution is formulated to withstand two
full calendar years of normal operation without draining or
adding inhibitors, and provides freezing protection to -20°F.
It is the owner's responsibility to keep the freeze protection
at a level commensurate with the area in which the vehicle
will be operated. Regardless of climate, system protection
should be maintained at least to 0°F., with an ethylene-glycol
COOLING SYSTEM CAPACITY
All cars except Fleetwood Seventy-Fives
with heater only 17 U.S. qts.
(14¼ Imperial qts.)
with Air Conditioner 17½ U.S. qts.
(14½ Imperial qts.)
without heater or Air Conditioner 16 U.S. qts.
(13½ Imperial qts.)
Fleetwood Seventy-Fives 20½ U.S. qts.
(17 Imperial qts.)
base coolant to provide adequate corrosion protection. When
adding solution due to loss of coolant for any reason or in
areas where temperatures lower than -20°F. may occur, a suf-
ficient amount of ethylene glycol base coolant that meets GM
Specification 1899-M, or equivalent, should be used.
Every two years the cooling system should be serviced by
flushing with plain water, then completely refilled with a
fresh solution of water and a high-quality, inhibited (permanent
type) glycol base coolant meeting GM Specification 1899-M,
and providing freezing protection at least to -20°F. At this
time, also add GM Cooling System Inhibitor and Sealer or
equivalent. In addition, Cooling System Inhibitor and Sealer
should be added every fall after the car has been driven 24,000
miles. GM Cooling System Inhibitor retards the formation of
rust or scale and is compatible with aluminum components.
NOTE: Alcohol or methanol base coolants or plain water
are not recommended for your Cadillac at any time.
PREVENTIVE
MAINTENANCE
Preventive maintenance for your Cadillac is based on the
Manufacturer's recommendations. Details are outlined in the
53