General Coolant Antifreeze question

evaporate => low temperature boiling

rate of evaporazation of varoius fluids can be compared. The MSDS designated standard material is butyl acetate with a vaporization rate designated as 1.0

pure water is 0.3 and most antifreeze are less than 0.03

So it can evaporate, just about 10 times less than water. I think some antifreezes now are about 0.01, thus 30 times less than water

As for a "closed" system, the recovery tank is NOT closed and will allow evaporation loss. A coolant system with a true pressure tank can be completely closed and thus no losses

I'd say due to advances in coolant technology. The anti-freeze in the past would break down over time.

Slow loss of coolant could be attributed to a small leak through the head gasket into the combustion chamber. Might also be attributed to an imperceptibly small leak in the radiator or plumbing that does not leave a puddle. I had a small leak in a radiator that I could smell, but never saw any drops on the garage floor until it got worse.

Seems like it would have to escape someplace. Where would it evaporate to?

for the Pantera, the original recovery tank is vented and thus vapor can escape.

Ahh. Forgot about that. I would imagine all systems have an overflow tube, thus AIR!

a properly sized REAL expansion tank system (with trapped air over the coolant) would not lift the cap and thus not have any losses.

I think that is design of a lot of newer cars

Some times it can be simple, make sure you have a high pressure cap on your expansion tank. The caps do wear out and then the unsealed tank can allow a lot of evaporation even a boil over.

quote:

Some times it can be simple, make sure you have a high pressure cap on your expansion tank. The caps do wear out and then the unsealed tank can allow a lot of evaporation even a boil over.

I think Chris hit the nail on the head... If you encountered a hot engine situation for whatever reason - e.g. sitting in stop and go traffic with a marginal fan - you would boil out some coolant through the overflow. This would require you to later top off your system. And this is only exacerbated if your pressure cap is not performing properly.

And as others have already pointed out, the Pantera cooling system is not a closed or sealed system.