Originally Posted by
mox
Seems to me that the authors of earlier posts here presume corrosion inhibitor and anti freeze in coolant are the same thing.
Corrosion inhibitors are important, especially in motors with components containing aluminium in the cooling system. However, anti freeze is sometimes unnecessary and at times can cause problems.
Am not sure what if any anti freeze is used other than ethylene glycol. Problems with it is being expensive and not as good for transferring heat as water. Have also seen claims that it tends to coat surfaces with a film that is a poor conductor of heat. Seems best not to use it when not necessary. In Australian winters not much anti freeze is needed compared with that normally required in many other countries wher prevailing temperatures get far lower. Apparently coolant containing one third ethylene glycol will protect down to minus 18 degrees - colder than the lowest ever officially recorded temperature in every state except NSW. A truckie /earthmoving contractor in Victorian snow country once commented to me that you don't need much.
Have not had anti freeze in my 300TDI since changing the timing belt 3 years ago. So far no need, but have been giving it protection such as parking under cover if a bad frost is likely. Not even the first problem as experienced in the very dry and cold 1982 drought has occurred, ie motor getting hot because of frozen radiator.