[Edwardsc1]

I have a 50i, so little bit different with respect to the engines, but I was having coolant loss issues as well, about as much as you are. I had to have my expansion tank replaced because there was a slight crack in the bottom of it, and I also had to have all my T-joint connections replaced as well because they were leaking.

Could also be a small leak in the radiator if there was a puncture from a rock, but that's probably not as likely.

Some of those plastic pieces begin to break after going through so many heat cycles over the years. I had my T-joints replaced with brass ones and have been good to.