When i check mine it not been driven that day and level is in middle i don,t add any i think it goes up and down when engine is in use and when engine cools down its back at original level in the 12 month service time i did not even add coolant i only did 3000km but i love the fact i did not even have to add any same goes for oil.I just check every now and then and the dealer does the rest i like the 12 month service interval these have.They even give it a was last time i did not notice till i got a call day or so after from the dealer to ask how was every thing going .That day it was a shower and my car is always clean and i did not know they washed it funny i thought .The polo has been one of the most reliable car i have owned and the sutherland vw service has been good from the first visit.Check it cold if its in the level lines its good i think there is a low sensor that has a dash warning light so don,t worry .