The first coolants
If you look for coolants in several retail stores you have a choice between many coolants in different colours. For example in orange, blue, green, yellow or purple. That seems to be a little bit weird because the first coolants had the same ingrediants and colour. They all based on a constant balance of ethylene glycol [EG] (also called Glycol / Glykol), water and additives. In there the silicate was a strong additive for corrosion protection. During that time the conventional antifreeze was compatible with every vehicle and peformed well in cooling the engine, preventing freezes, secure the heat transfer and protecting the cooling system against corrosion.
The first mixture advancement used less toxic EG and more of the expensive chemical polypropylene glycol [PG]. From that time both coolants found their difference in the chemical basic of EG and PG.
Because both coolants used silicate, they were declared under the Inoganic Acid Technology [IAT] (inoganic acid technology]. That technology refer to the use of anorganic silicate acid.
Hows does the protection of an antifreeze work?
The coolant creates a protection film between the metal material and cooling lubricant. That prohibits an electonic exchange of different precious metals and disable a stonger corrosion. Additionally it prevents the appearance of „red mud“. The red mud deposit would plug the channels or emery metals and produce more corrosion.
The main issue of the first coolant was the short additives lifetime. A coolant exchange after 3 years or 60.000 kilometers was necessary.
The new form of antifreeze
The search for a longtime coolant began. The solution was an organic acid. The chemical basic of EG and PG didn´t change but the silicate (inorganic acid) was replaced by oganic ingrediants like carboxylate. The first Organic Acid Technology [OAT] coolant was designed! Their special character was the silicate free mixture. From now on the organic acids were responsible for corrosion protection. The lifetime change from 3 years and 60.000 kilometers to 5 years and 240.000 kilometers. As a result these coolants were called „Long Life Coolant“ (LLC) or „Extended Life Coolant“ (ELC).
Coolant colours as standard
A famous mistake lays in the understanding of coolant / antifreeze colours as indicator of their chenmical basic. That´s easily wrong! So not every orange colour indicates an organic acid or something like that. Every single coolant manufacturer uses own colour mixtures and is free in their use. Colours could just indicate differences inside of a manufacturer poduct line (compare VW and BASF coolants /antifreezes).
Index number as standard
Worldwide identicial index numbers don´t exist. So for example the german car manufacturer VW and the worldwide largest chemical concern BASF developed own internal coolant standards. These ones established over the time and can be used as a navigation.
An overview of these antifreeze standards:
VW standards: G11, G12, G12+, G12++, G13
BASF standards: G48, G30, G40, G05, G33, G34
Own standards don´t explain completely different standards. For the G11 and G48 coolant, a very similar glycol mixture is used. Also the G12+ and G30 plus the G12++ and G40 are similar. The following table presents a more detailed overview:
VW and BASF coolant/ antifreeze standards:
|G11||G48||green/ blue- green||Standard for coolant with inorganic acids.|
|G12||red/pink||Volkswagens first coolant with OAT formula and free of silicate. Do not mix it with G11 coolants! Agressive chemical reactions attack the cooling system and the lubricant would clump together.|
As reaction of the mixture problems between G11 and G12, the G12+ was designed. It can be mixed with G11 and G11 coolants. It is free of silicate.
|G12++||G40||red/violet||The successor of the G12+ coolant was used in every VW and Audi car. It shows an improved corrosion protection, higher boiling point (135 degrees) and better heat dissipation.|
|G13||purple||The glycol based G12++ was replaced by the glycerol based G13 coolant. The advantage of the G13 lays in a better economic safety and lower production costs.|
|G05||yellow||Has the special advantage of a cast iron engine compatibility|
|G33||blue- green||Special coolant/antifreeze formula for Peugeot and Citroen cars. The silicate free colant has t the same colour as the G11/G48 but different ingrediants.|
|G43||orange||Special antifreeze for General Motors and Opel cars|
Some questions still exist: What ist he difference between these manufacturer approvals? Which antifreeze can be used if no one of these is recommended form y car? Additionally some car manufacturers produce coolants without any approvals (e.g: BMW recommends own products withour any declaration of ingrediants or additives) or use their own approvals (for example Mercedes Benz with MB 325.0). Some more examples are Mopar Coolants, Nissan Antifreeze and Honda Coolants. An easy transparency of these multiple standards is just missing. From manufacturer perspecitve, these missing uniform standards are very lucrative, becuase the customers prefer to buy the manufacturer recommended coolants and no less expensive ones. Independent manufacturers try to focus on the big amount of manufacturer approvals and declare these on their product labels. Or use similar approvals to indicate the original coolant approval (Like Ravenol uses C11 for G11 of VW).
Which coolant can I use for my car?
Thats exactly the question, many car owner ask themself. A drive to the next repair shop would deliver a simple solution. But mostly they only sell the expensive OEM products for expensive prices. The best way for you ist o have a look into the service manual of your car. It will give you the needed informations about a suitable coolant. If it delivers informations about a organic acid based coolant, consumers can check the product informations of independent antifreeze manufacturers.
Concentrate of ready mixed coolants
The purchase of a coolant delivers the choice between concentrate and ready mixed antifreezes. The concentrate is the pure coolant lubricant. A refill just with the concentrate is not recommended. The pure concentrate hits the freezing point earlier and the heat transfer reduced. An engine breakdown follows. So mix up the pure concentrate with water. But take care, because also water has different attitudes. Do not use hard tap water, becuase if leaves deposits. Distilled water has the best quality for this application. With the right water, a mixture proportion of 40/60 or 60/40 is usual.
Can I just use water? That is not recommended! At minus temperatures, the water would freeze and damges the mechanic. Seals and tubes get damaged, too. If you are not interested to mix the coolant concentrate with water, the ready mixed coolant represents the best alternative. It has the conventional mixing balance and is ready to use.
Consequences of a wrong antifreeze
By using the wrong coolant, bad things can happen. Metals inside of the cooling system can be attacted, stronger corrosion comes up and the cooling system gets blocked. An engine breakdown can follow. Also the mixture of different coolants can be a problem. New additives of a different antifreeze can react with the old fluid and produce a strong corrosion.
To work with the theoretical knowledge in pactice, we had a look for the service manual of a Volkswagen Golf. In there, the important informations for a suitable antifreeze are named.
VW Golf - Coolant
For the Golf VII, Volkswagen recommends his own VW Coolant G13. Like we told before, other manufacturer try to copy these approvals and mix a similar coolant. So an adequate alternative is the Ravenol LGC Antifreeze C13.
Antifreeze / Coolant conclusion
The time shows that the first coolants found a strong change. New chemical additives and different colours represent the currenty offer of automobile coolants. Missing international standards are a seroius disadvantage for all consumers. Not available informations about ingredients and additives complicates the search for the right coolant. But if you have a look for the general basics of antifreeze characterisitcs, you can find the right coolant easliy.
The manufacturer Ravenol offers a very good coolant overview. It shows which coolant is suitble for your car.