The G12 and G12+ coolants (pink coolant) used by Volkswagen are OAT coolants. The biggest ace up its sleeve however was the fact that OAT offered superior protection to aluminium under high temperatures, a property that would exhort many manufacturers to shift from IAT to OAT. Organic Acid Technology ensured that the coolant itself was composed of non-degradable chemicals (thus addressing the fundamental issue that IAT brought to the table), while also being silicate, borate and nitrite free, further preventing any chances of increase in electric conductivity with ageing and the rusting that followed. Organic Acid technology was the answer to the previous bottleneck. It does a better job of controlling rust formation in older engines with iron blocks and has additives in the form of silicates and phosphates. The green coolant used by many manufacturers even today is ethylene glycol. This is not to say that Ethylene Glycol isn’t used in today’s cooling systems. Thus, started the hunt for a liquid which would further last a lot longer. An electrically conductive liquid when in contact with the iron present in the engine block would be the perfect recipe for rust formation The more lethal property of Ethylene Glycol was that its disintegration would exponentially increase its electrical conductivity.Firstly, its chemical composition meant it would disintegrate and lose its properties, thus requiring a change every 2-3 years.

Ethylene Glycol however brought about two other minor headaches: This means the fundamental issues of early freezing (due to inherent properties of water) and early boiling (due to properties of alcohol) stood solved. Ethylene glycol-based coolant is called “Inorganic Acid Technology based coolant” because it contains silicates and phosphates in order to comply with the metal parts in a cooling system.Īn Ethylene Glycol and water mixture (in a 60:40 ratio) would freeze at -45 degrees Celsius (thus beating even alcohol in this regard) and boil at well over 100 degrees Celsius. The answer to this predicament was (and still in many cases) is ethylene glycol. There was a need for a liquid that would offer the depression in freezing point normal alcohol such as ethanol would, yet not boil over early like the former did when it formed a mixture with water. Inorganic Acid Technology (Ethylene Glycol) Unfortunately, the boiling point of alcohol was much lower than water, which would mean the resulting mixture would also boil very early (around 80 degrees Celsius), needing frequent top-ups. Alcohol formed a mixture with water which would lead to a “depression” in freezing point, thereby preventing freezing. In order to overcome the former, alcohol was added to water and used as a coolant. This would also impact the heat transfer (by forming oxides) and cause issues in both the radiator and engine block. This rust would eventually choke the radiator over time too.

Secondly, water would react with the iron present in the engine block and form rust.

This means it would freeze and block cooling system pipes and radiators in the winters.

Firstly, water has a comparatively high freezing point of 0 degrees Celsius.

There were two downsides or shortcoming however: The high specific heat capacity ensured it could transfer a large amount of heat easily from the engine block to the radiator. Water with its high specific heat capacity (which basically means it needs a lot of heat in comparison to other liquids in order to raise its temperature by a specific amount) was perfect for car radiators in theory.

In the olden days, the word “coolant” simply implied “water”. It’s a fluid that is second only to engine oil in an internal combustion engine, yet is ignored most of the times. A very simple yet crucial component in the era of modern (comparatively) high compression ratio engines. Thanks to him for the expert inputs!Ĭoolant. This thread has been jointly compiled with BHPian Vigsom. BHPian vishy76 recently shared this with other BHPians.

Does orange coolant turn pink