[whataboutbob]

Originally Posted by Laika

Damnit. They topped it off but didn't use Subaru Blue coolant. Hopefully it's an equivalent.

From what I could tell, coolant temp is getting to operating temp faster but I'm trying to rationalize this maybe someone else can chime in.

Ideal gas law tells us that PV=nRT (pressure, volume, n=moles, r=constant, temp)

Volume of the vessel holding the coolant stayed constant but the moles of coolant went up so in a closed state pressure increases.


Now I need a car guy to tell me if the coolant "Vessel" is actually closed. Does the car have an overflow hose or anything? Even something to relieve pressure?

Nice job quoting the Ideal Gas Law. Not related, but it expresses the point.