Expansion tank question

[Gunslinger]

G13 coolant is not recommended for cars with brass or copper cooling systems and heaters.  You should use a good ethylene glycol coolant for older cars.  You'll have to change it more often than the long life types but its chemical makeup won't attack the cooling system components or cause clogs.

[Kodjo]

42 minutes ago, Gunslinger said:

G13 coolant is not recommended for cars with brass or copper cooling systems and heaters.  You should use a good ethylene glycol coolant for older cars.  You'll have to change it more often than the long life types but its chemical makeup won't attack the cooling system components or cause clogs.

So, up to 12++ would be safe as these are made of Glycol. G13 is made of Glycerol. Is that the difference?

[Gunslinger]

There's ethylene glycol and propylene glycol.  I don't know anything about Glycerol...it may just be a trade name for one.  There re some coolants...like GM's Dex-Cool...that are not compatible with ethylene glycol coolants at all...mixing them will create a cloudy mess that forms clogs and GM had a real issue with aluminum engines overheating and blowing due to not adequately alerting owners and non-GM dealer techs about the issue.  Unless one completely flushes the system and changes hoses and anything else internal to the cooling passages mixing types is not recommended.  Stick with what's appropriate for the year, make and model.

[Kodjo]

I'll put G11 in it then, after flushing the complete system with water. Thanks for the confirmation!

PS: Glycerol + 20% H2O = glicerine

https://en.wikipedia.org/wiki/Glycerol