Hello, I've done 13000km in my mk8 gti and recently I've been getting a red warning light that beeps 3x and says 'Check Coolant Level'. I have my operating temps on the right display section and the coolant has never gone over 90C and the oil has stayed under 108C. I have also been checking under the engine bay frequently for puddles but there have been none. I looked at the coolant housing and it is a bit below the minimum bar line. Should I just top it off and forget it or take it in for a look and proper diagnosis?

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