I don't know of a single car made in the last 10 years where it's normal to lose "half a cup over every few months." Every car I or my family have owned in the

I don't know of a single car made in the last 10 years where it's normal to lose "half a cup over every few months." Every car I or my family have owned in the last thirty years has never needed coolant added to it over years of ownership. Water pumps "weeping" coolant is a sign of failed seal, not by design. The GP commenter's buddy was sold a car by someone who was trying to pass off a needed repair; likely a leaking radiator or failing head gasket if they were unlucky. If they were lucky: a bad radiator cap or a failing coolant system hose. If they were really, really unlucky: a failing heater core.