Kona Coolant Loss

I had a similar problem on my old Opel Astra, though it wasn't quite the same setup. The coolant light kept coming on and I was constantly topping it off. Turned out to be a tiny crack in one of the radiator hoses that only leaked when the system was fully pressurized. It was incredibly difficult to spot. Have you pressure tested the cooling system, or looked for any residue near the water pump and around the cooling fan after a drive? Sometimes, air pockets can cause false low readings too.

That’s helpful, thank you! I haven't pressure tested the system. Is that something readily doable at home, or does it require specialized equipment? And should I also keep the cooling fan in mind?

Pressure testing does require a special kit, which you can either buy or often rent from an auto parts store. It hooks up to the radiator and allows you to pump air into the system to check for pressure drops. Given what you've described, it's probably best to take it to a workshop, since you've already checked the obvious stuff, and a pressure test will help pinpoint the exact location of the leak.

Thank you for the advice regarding the pressure test and potential hairline crack. I took it to my local shop; turns out the water pump was leaking slightly, causing the coolant loss. Replacement plus coolant came to 52€. Problem solved!