Richard D Gorscak

I bought a 1967 Jaguar XKE rated by inspectors to be in excellent (not mint) condition. No one drove the car far. Two separate mechanics who worked on it filled the radiator (I guess in through the expansion tank). The first firm was a reputable antique restorer, but 100 miles away where I bought the car. If the car idles for an hour there is no problem, but if I drive car on highway (60+ mph) for over 20 miles and then put car in garage, a lot of antifreeze comes out onto the garage floor (a flood). The car engine thermostat does not show the car being hot and it runs well. I had the thermostat tested for temperature using infrared heat sensor and they agree. There is still some antifreeze in the expansion tank and my last mechanic wonders if that is just the right amount. How much antifreeze should be in the expansion tank. The user manual says to the lip of the cap, but that means it would be full. How can it be an expansion tank if already filled?