Description:
The
most common formulation of antifreeze is green in color and uses
ethylene glycol as a base with anti-corrosion additives
mixed in. The ethylene glycol part of the formula provides
crucial anti-freezing characteristics and the additives deliver the anti-rust and anti-corrosion
capabilities. Beginning with 1995 models, most GM vehicles started coming from
the factory filled with an extended-life antifreeze, trademarked as DEX-COOL®. Distinctively
different in appearance, DEX-COOL®, and its
aftermarket equivalents, is an orange/amber color. It
still uses ethylene glycol as a base, but
contains a different additive
package than standard green-colored antifreeze. This coolant is designed to protect cooling
systems for up to 150,000 miles or
five years. Other antifreeze
formulations include silicate-free for Japanese cars and phosphate-free
for European cars.
Purpose:
When
properly mixed, antifreeze
and water provide excellent anti-freeze, anti-boil and anticorrosive
properties.
Maintenance Tips/Suggestions: Check your owner's manual for antifreeze
usage specifications. Antifreeze, when mixed at a 50/50 ratio with
water, provides excellent anti-freeze, anti-boil, and anti-corrosive
properties. In extremely cold environments, the ratio for standard
ethylene glycol can go as high as 70% antifreeze, 30% water. With
DEX-COOL®, the maximum ratio of antifreeze to water is 60/40.
Although DEX-COOL® type antifreeze can be mixed with standard
ethylene glycol antifreeze, DEX-COOL® loses its 5 yr./150,000 life.
As such, it's best not to mix antifreeze types unless absolutely
necessary. All coolants must be diluted with water at the proper
ratios and should not be used full-strength. Full-strength antifreeze actually
has a lower freeze point than when mixed with water.
Generally, standard ethylene glycol type antifreeze should be changed
every two years or 24,000 miles. Even though the coolant freeze protection may
test OK with a hydrometer (freeze protection only drops with extreme dilution,
not with age), the additives break down over time. When changing coolant,
it also presents an opportune time to replace bad cooling system hoses.
Leaking, brittle, spongy, cracked, or rotted hoses should be replaced before new antifreeze is
installed. Hose clamp connections should also be checked to ensure that they're
secure and free from leaks. If you decide to service your cooling system yourself,
use extreme caution: Opening a hot radiator or coolant reservoir/overflow tank
can cause severe burns. Be sure that both the engine and cooling system
are cool before you begin
any heating/cooling system maintenance or repairs. Because of
lower hood profiles and cramped engine quarters, it's also possible
that your
car
may be equipped with an air bleed for the cooling system. Unless
the cooling system is bled properly, air may stay trapped
in the system and cause erratic temperatures,
or in extreme cases, engine or cooling system damage. If
you're unsure about any aspect of cooling
system service, don't take a chance. Have your car looked
at by a professional service technician.