You should never run your cooling system with anything more than a 50/50 mixture of anti-freeze and soft water. Any other mixture will give you a lower boiling point and a higher freezing point. If your car has less than a 50/50 mixture it is OK to put some anti-freeze in but normally you should just cut it in half and top off. If you have a drip you have a leak that must be attended to. It might be as simple as tightening a hose clamp or it could be a warning that one of the plastic end tanks is about to blow off! You cannot afford to ignore ANY leak even minor ones. Remember that the system is pressureized up to 15 psi and while that may not sound like much you would be impressed if a hose broke off and the coolant flashed into steam! Last summer on the Rhode Island Rally one of the cars blew off a radiater tank and it looked for a second like the car was on fire, it was enveloped in a cloud of steam and there was nothing we could do to help him. He had to wait till Rob Grady got home to send him a new radiater. It is much better to fix your car in your garage than on the road! David Teitelbaum vin 10757