BMW Repair: BMW 325i coolant, bmw 325i, coolant

Question
1991 110,000 325i
takes coolant every other week
no visible leak
no over heating
what is it?

Answer
Sounds really strange not being able to notice where the leak is.Depending on how much coolant you say you are losing.If it is gallons it is bad ,if it is a cup of so I would say you need to really examine the hoses for tightness.And really check the water pump that is probably the culprit