(Note: coolant and antifreeze refer to the same product, in below freezing, coolant lowers the freeze point hence the name anti-freeze and in warm weather coolant helps raise the boiling point, "coolant") There are many types of engine coolant, colors range from the old standard green to the blue coolant in the newew Mercedes and BMW cars. All engine coolants help guard against corrosion and overheating if maintained properly. Some of the main differences between the green coolant and the newer mixes is the chemicals made to create the coolant. The new red, blue and yellow coolants are more environmentally friendly and designed to last longer between services. All engine coolants are highly toxic and should be kept away from animals or dumped down the drain. You should not mix the different coolant types, if your engine came with red coolant then you should add red coolant only. The manufacturers of Dexcool (red) have had a problem with the coolant lasting as long as it should, depending on the climate and driving conditions the coolant can decompose causing coolant passage blockage in the radiator and engine block. To avoid this problem simply change your coolant more often then the recommended 100,000 miles. Change your coolant every 40,000 miles to prevent this problem. All engine coolant must be replaced on a normal schedule to avoid aging coolant changing its chemical base composition to a acid base. This condition will cause the coolant to eat away at internal engine parts, water pump seals, intake manifold and head gaskets, causing premature engine failure. The coolant mixture to water should be about 60% coolant to 40% water. Always add and check coolant level in the coolant reservoir when the vehicle is cold. Be careful of harsh cooling system chemical flushes because they can cause more damage then good, especially to aluminum heads, intake manifolds and the engine block. Always read the warning label carefully before using any brand of coolant. Engine coolant colors can vary from green, orange, blue and yellow each having there own unique protective and environmental properties.