Dan Tumms (Portland, Oregon) - 1992 Honda Civic
A cooling question. Every week and a half, he checks his overflow reservoir, and, it's empty. The car isn't running hot, the radiator is full, and he doesn't see any signs of where it might be leaking. Is it just an anomaly? No, he's got a problem, and it could be serious. If he's very lucky, could be just a pinhole leak in the reservoir, causing a very slow leak. If he's less lucky, could be a loose hose clamp. If he's really unlucky, a leaky head gasket or cracked block.