Small coolant leak

[qwertyjjj]

I seem to have to top up my coolant once a year V with about 500ml of coolant.
Is this a bad leak or can I just continue topping it to max every 12 months?
I can't see any leaks under the car.

[abscate]

Since you are replacing your coolant every 40,000 km.....

Assuming you are driving about 20,000 km per year, thats not a leak worth chasing. If you inspect very carefully, you might find white residue near a small seep near a hose joint, thermostat, or water pump.