HI, I wonder if someone could help me out with a long standing problem, I´ve got a Triumph Thunderbird ´ 97, for the last 6 months it seems to be losing coolant at a ridiculous rate, I top the overflow tank up to between the two lines, after about a 100 miles or so the coolant level has gone down to about an inch off the bottom, there are no leaks that would produce this amount of coolant loss, the engine has been pressure tested for leaks and is fine, I hope you can advice me as to what is going wrong, Cheers.