Air largely follows that trend, air expands when hot, and its density decreases, and its viscosity increases, when air is cold it's density increases, it's viscosity decreases. Now air pressure affects the boiling point of water, so colder air being denser would exert more pressure on water, also the colder temperatures would be less prone to evaporation. As air pressure decreases(due to heat), it helps water evaporate as there's less pressure containing it, but as water evaporates it takes heat with it, so it becomes a self limiting system.

 

Evaporation. The overflow tank is not sealed. When the radiator cap relieves, due to system fluid expansion, it dumps hot fluid/steam into the tube leading to the overflow tank. The tube goes thru the overflow tank cap where it is submerged (a vacuum system is created) in cooler fluid. The cooling system is “closed” because this vacuum. But the overflow tank is not “closed”. Each time hot fluid cycles through the overflow tank, the fluid in the tanks warms causing a small amount of fluid to evaporate through the cap.. It escapes at through the cap where the hose passes through. You can see white residue by the feed through on the outside of the tank cap.
Utah

 

Because Spoon blue hoses
Those are made of a compound (ethylene, propylene rubber) so they're not silicone...?

 

So, Spoon hoses don't have the porosity of silicone hoses?

Thanks!

 

Spoon hoses are advertised as SEP (Silicone Ethylene Propylene) rubber and rated for up to 160c compared to 120c stock EPDM.
Samco's are rated at 180c.

Can anyone confirm whether the Spoons permeate?

 

That is a good question my friend!

On OEM hoses for the past 24 years now (MY 00 AP1) and they still look new so...if it ain't broke

 

Thanks for clarifying what the S stands for.

 

"Let sleeping dogs lie," has merit.