Different coloured anti-freeze

[michael glynn]

Hello all, is there any significance in the colour of coolant? I’ve seen fluorescent Green, Pink, Blue and some others.
I overheard a conversation in which a guy was told not to mix colours as not all are compatible.
Since mine is due for changing I was interested. Thanks for any help.

Topic

[Mike]

The colors are there to help prevent mixing of the various different kinds of coolant and to identify if there has been any contamination of coolant. Most of them are still based on Ethylene Glycol but have newer additive packages to better prevent aluminum corrosion, since modern engines are all aluminum. Some are based of Propylene Glycol, which is a less toxic chemical that alters the freezing/boiling point of water, albeit not quite as effectively as Ethylene Glycol. It’s used more frequently in Marine/RV antifreeze and is usually dyed pink.

All the manufacturers say not to mix anything, but never say why not to or what the consequences will be. I have never conducted any experiments mixing coolants myself, so I’m afraid I’m with everyone else who is only in a position to speculate on that. Your first issue would be identifying what is supposed to be in whatever car you have so you can go to the dealer and buy their antifreeze. I would only buy something else if the whole system was being drained and rinsed with the thermostat removed, so the antifreeze could be completely replaced with the new stuff. Of course you would want to have a reason why the factory antifreeze isn’t ideal before doing that.

Some more spotty information here: http://en.wikipedia.org/wiki/Antifreeze

[James Cheyne]

“15. What could happen if I mix two different colours of antifreeze in my radiator?
If two different colours of antifreeze are mixed together, not only will it discolour and look brown or cloudy, it could also cause problems with the cooling system if they contain non-compatible corrosion inhibitors. The different colours of antifreeze usually help distinguish between different corrosion inhibitors. EcoFreez makes a Global Premium Coolant, yellow in colour, which is safe to mix with both conventional and OAT coolants and takes on the dominant colour of antifreeze in the radiator.”

Quoted from the following article: http://foryourbusiness.eco-freez.com/index.php?option=com_content&view=article&id=118&Itemid=134

More info: http://blog.chiltondiy.com/2013/06/which-antifreeze-is-right-for-your-vehicle/

http://www.machinerylubrication.com/Read/841/coolant-fundamentals

http://bioengr.ag.utk.edu/Extension/ExtProg/Machinery/Articles/engcool.htm

🙂

[Ingvar]

Yes, they are coloured differently because of allegedly different chemical combination.
In reality, you can mix Prestone with ANY antifreeze out there, including the so much dreaded Dexcool.

[Author]

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