I own an Infinity QX4. It has a very small (1 gallon/year) leak of coolant from what appears the head gasket. The car runs great - I just keep the coolant reservoir at MAX line. It recently passed smog, there is no smoke or water from exhaust, the coolant is green (no signs of oil in it) and the oil and oil cap are normal (no milkiness or discoloration). I would like to seal the head gasket leak and avoid the cost of replacing the head gasket, etc. Any suggestions? Which sealer is best? Do the ones that do not require draining the coolant from the care work?

One member recently used one of those products and said it worked. I have no experience with them.