Losing coolant every few weeks

[aman23]

Hi guys.

My cars losing a really small amount of coolant but there's no leaks I can see anywhere.

When I say small, it takes about 300 ml to get it back up to the Max mark. This is happening about evey two weeks.

The coolant is still pink and looks OK. I changed it about a year ago when I did the timing belt.

Could it be there's a leak somewhere but its not showing up because its only a small amount? There's no white smoke but I'm getting worried as its only started in the last 6 to 8 weeks.

Thanks guys.

2003 130 awx.