I think I refilled my WRX coolant too fast --- the header tank should help bleeding but several times today my temp went up to 2/3 and suddenly back down.
I am going to wait overnight and check it cold in the morning.
All the levels are ok. (both in the header tank and the expansion tank).
Do the air pockets eventually get swept out and the system self-bled? Or do I have to drain the whole flippin' thing and refill it really s-l-o-w-l-y.
[I had to drain some coolant as I was fitting the engine block heater (TBird rally coming up).]