Quote:
Originally Posted by Ron Kwas
RiM;
Maybe the Evans hi glycol content product doesn't expand quite as much as the normal glycol/water mix, but if coolant was being lost out the overflow
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Ron
The volumetric expansion coefficient of ethylene glycol is actually higher than that of water.
https://www.engineeringtoolbox.com/c...ts-d_1262.html
I didn't go looking for the expansion coefficients for the other glycol blends that Evans uses. What is significantly different is the boiling point. Ethylene Glycol boils at approximately 198 C at atmospheric pressure so, twice that of water. I think Evans advertises that their boiling point is a nudge lower than that. So, if your engine overheats the ethylene glycol will expand and if it expands beyond the space available in the cooling system it will just burp a little coolant out. You will not get a boil over. The engine will have to get really stink'n hot to get to the Evans coolant to boil which would result in a 'boil over'. If your engine ever got to the point that the Evans coolant went into a full boil I expect that the oil would be so hot that you would probably have a lubrication failure or the engine would be detonating like crazy under load..
I expect that the problem with Rustinmotions Alfa
might be that the radiator may be undersized or the radiator airflow insufficient to handle the cooling requirements of the engine at slow speeds / stop and go traffic resulting in the conventional coolant mix entering a boil condition .(50:50 coolant mixes boil around 120C - 125C at atmospheric pressure). Vintage Italian cars were not meant to be driven slowly**. The higher boiling point on the Evans coolant suppresses boiling during these conditions. The Evans might suppress boil overs; but, I expect that the cooling system operating temperature will now be running slightly higher than they were before.
** As I recall, the Jag XKE, particularly the later 12 cylinder versions were known for boiling over in slow speed traffic. Fitting a pile of electric fans on the radiator was a popular retrofit. Sounded like a giant vacuum cleaner when the fans kicked in at idle.