FYI on anti-freeze color:

 http://www.eetcorp.com/antifreeze/antifreeze-faq.htm

 In the past, most antifreezes were green. Now, manufacturers use
 a variety of colors in their antifreeze product lines. Green
 generally, but not necessarily, indicates an automotive or light
 duty formulation. Orange antifreeze generally means extended-life
 type of antifreeze. It is ethylene glycol-based like most green
 antifreezes but contains different corrosion inhibitors.

 The various manufacturers use colors to identify their products
 in a bit of marketing gamesmanship; however, there are no hard
 rules governing the use of these colors. Equipment manufacturers
 and consumers should have an ability to identify their approved
fluid.

 In addition, color has been used in antifreezes as a safety measure
 to discourage accidental ingestion.

 Since the mid-1990�s, the proliferation of coolant colors has caused
 considerable confusion. All engine coolants use a glycol base but
 include different performance additives that inhibit (control)
 scale/ corrosion. Believe it or not, all of these coolants are
 clear, water white before dye is added.

 The traditional green coolant is based on inorganic additives
 and is called inorganic additive technology (IAT). It is a tried
 and proven chemistry that provides a fast acting protective film.
 The additives deplete, though, and need to be replenished every
 couple of years.

 Fully formulated engine coolants were developed in response to user
 demands for a simpler, universal, longer life coolant technology.
 Heavy-duty operators had to use low silicate automotive coolant
 formulations (high silicate automotive antifreezes could cause
 �green goo� in diesel engines) that required a separate SCA additive.

 This often resulted in mixing errors when the SCA was added at
 initial fill or when topping-off. Unlike automotive antifreeze,
 fully formulated coolants are pre-charged with SCA�s and contain
 all of the ingredients necessary to protect diesel, gasoline,
 and gaseous fuel engines. Pink has become recognized as the color
 for fully formulated coolant, although they are also commercially
 available in green (as required by government agencies). These
 products meet performance requirements for major automotive
 specifications, allowing mixed-fleet operators to stock one
 antifreeze formula for all of their vehicles.

 A new type of antifreeze, referred to as extended or long life,
 has emerged. Its unique chemistry differs significantly from that
 used in traditional antifreezes. Referred to as organic acid
 technology (OAT), this new chemistry uses organic acids to protect
 cooling system metals. Extended life antifreezes have been colored
 red or orange depending on the supplier; however, more colors may
 be used in the future. While these fluids do not deplete during
 service, they also do not protect as quickly as IAT coolants.
 These differences require a significant change in procedures
 used to maintain the cooling system.

 General Motors� has been using this technology (DEX-COOL�) in their
 cars and trucks since 1996. They use an orange dye for DEX-COOL�
 product. A Ford Motor Company� study concluded that OAT coolants
 �do not offer any significant advantages for the consumer�� and
 ��current coolant corrosion protection can be extended far beyond
 previous expectations�. Cummins Engine Company announced in a memo
 dated July 16,1999, that OAT coolants are not compatible with their
 engines. Cummins is reporting that these long life antifreezes
 cause degradation of silicone seals in their engines after 80,000
 to 100,000 miles of service. Cummins, therefore, is not recommending
 the use of OAT coolants in their engines.

 Hybrid organic acid technology (HOAT) uses both inorganic and
 organic acid additives for long life protection. The objective
 with HOAT is to provide excellent all around protection and
 extended drain intervals. HOAT coolants generally can replace
 or are compatible with green IAT in older vehicles. Chrysler
 used conventional green IAT coolant until 2001, when they
 adopted G-05�, a hybrid coolant. Ford followed suit in 2002,
 dropping the green IAT for G-05� factory fill and extending
 the drain interval. Variations of HOAT coolants have been
 around for more than 50 years.

 Or....
 http://www.filtercouncil.org/techdata/tsbs/05-2.pdf

 Inorganic Acid Technology (IAT) is the chemical composition for the
traditional
 antifreezes that are green in color. An IAT can be used with either
ethylene glycol
 (EG) or propylene glycol (PG). The normal IAT service life is two
years or 30,000
 miles (50,000 km).

 Organic Acid Technology (OAT) was the first LLC / ELC introduced in
North
 America in 1994. OAT antifreeze had been widely used in Europe before
its
 introduction in North America. OAT can be either EG or PG but is
mostly EG
 based. Its first dye colors were orange and red. These dye colors are
still used by
 General Motors and Caterpillar. Green, pink and blue have been added
to the list
 of available OAT antifreezes. It is recommended that OAT not be mixed
with any
 other antifreeze technology. The normal OAT antifreeze service life
is 5 years or
 150,000 miles (250,000 km).

 Hybrid Organic Acid Technology (HOAT) is a combination of IAT and OAT
with
 nitrites added. This makes HOAT suitable for use in both light duty
and heavy
 duty systems. Currently, two manufacturers are using HOAT for their
vehicles.
 Daimler/Chrysler's version is dyed orange and contains 10% recycled
antifreeze.
 Ford Motor Company�s version is dyed yellow and does not contain any
recycled
 antifreeze. Both of these HOAT antifreezes use the marketing
designator of GO-5.
 They are compatible with each other but mixing them with IAT or OAT
is not
 recommended. The normal HOAT antifreeze service life is 5 years or
150,000
 miles (250,000 km).

 Nitrated Organic Acid Technology (NOAT) is an OAT with nitrates
added. This
 makes NOAT also suitable for use in both light duty and heavy duty
systems.
 NOAT and HOAT are very similar in performance characteristics.
Currently, no
 OEM vehicle manufacturer is using NOAT. The normal NOAT service life
is 5
 years or 150,000 miles (250,000 km).

 Since antifreeze is clear when it is manufactured, and water is
clear, dye is used
 to color the antifreeze for identification and marketing purposes.
The color of
 antifreeze is no longer an accurate indicator as to whether it is an
IAT, OAT,
 HOAT or NOAT formulation. Further, some antifreeze manufacturers
market a
 �universal� antifreeze they say is compatible with all OAT, HOAT and
NOAT
 formulations. These "universal" formulas are not for use with IAT and
they will not
 convert an IAT to an LLC/ELC antifreeze. Mixing IAT with OAT, HOAT or
NOAT
 antifreezes will not damage your vehicle�s cooling system; however
the mixture
 will negate the long life/extended life attributes of these
formulations.

 In conclusion, there are currently
    two oranges,
    two reds,
    green,
    dark green,
    yellow,
    blue,
    blue-green,
    clear
 and
    pink
 dye colors available.