Aren't they all the same stuff, with different dyes ?
That's what I originally thought hence this posting, but have been doing some research in light of installing a new aluminium rad and this is what I have learn't: they don't mix:
Most antifreeze and coolant products on the market are ethylene glycol based with additives to prevent corrosion, lubricate seals and water pumps and aid in heat transfer to the coolant from the metal of the engine. Antifreeze coolant should typically be mixed with water at the ratio of one part antifreeze to one part water. This gives antifreeze protection down to minus 34 degrees and overheating / boil over protection up to 265 degrees. Do not use pure antifreeze in a cooling system without using at least 30 percent water in the mixture.
Most antifreeze coolant sold in recent years has been the traditional green coolant which has a life span of two to three years or up to 30,000 miles. Green antifreeze contains silicates, phosphates and borates as corrosion inhibitors to keep the solution alkaline. As long as the solution remains alkaline, corrosion is controlled and the cooling system is protected. Over time corrosion inhibitors are depleted and the corrosion protection is lost, therefore green antifreeze should be changed every two years.
Aluminium is especially vulnerable to corrosion and many vehicles have heads, radiators and other aluminium components in the cooling system. If the coolant in an engine cooling system is changed before corrosion inhibitors reach dangerously low levels, corrosion damage is prevented.
Long Life Antifreeze
An alternative to tradition green antifreeze is a product currently used by many vehicle manufacturers. Orange or Red antifreeze known as long life or extended life antifreeze increases the useful life of engine coolant. Long life antifreeze is also ethylene glycol based.
The difference between the two colours is that Orange / Red antifreeze contains a different type of corrosion inhibitor that has a much longer life than silicates, phosphates and borates. Orange / Red antifreeze contains organic acids that protect engine parts from corrosion.
Green antifreeze does not mix with long life antifreeze. Never mix the two colours in a cooling system. The organic acids in orange types will cause precipitation of silicates in the green type and corrosion protection is greatly reduced.
Orange type antifreezes are suitable for up to five years or 100,000 miles. They can also be used in many older vehicles if all of the green antifreeze is flushed from the system and is replaced with the orange / red antifreeze. The lifespan of long life antifreeze is about four years or 60,000 miles in older cars.
If you have doubts about switching from the green type of antifreeze to long life antifreeze, contact you retailer or car dealer and ask about compatibility with your cooling system. You can also contact Tetrosyl by email for further advice and technical support.
The level of protection of the coolant has little relevance to the corrosion protection. An antifreeze tester may show adequate frost protection but cannot test for corrosion protection which is depleted over time.
Change your coolant mix on a schedule based on the colour of the antifreeze you are using. Severe corrosion to engine and cooling system components can occur with resulting expensive repairs.