I've researched as much as I can but I still can't a clear answer. I have a 2012 sti. What is the correct method to measure the coolant level? Is it supposed to be done on a cold motor? Is the amount supposed to be in the middle of the empty-full lines on the white plastic tank? How do I tell if I have a coolants leak as opposed to just an overfilled coolant? The car drives normally, and I'm monitoring the coolant temp via ap.

 

I let the vehicle reach operating temperature and topped it off at full mark. rubber hose expand and contract depending on the temperature . Do a coolant pressure system test if you feel like your losing coolant .