86 Olds Calais 2.5: trans fluid leak. Fixed when I had it. Fixed again after my parents gave it to my little brother. Fixed again when he gave the car back to me. One mechanic he and his wife used refused to even attempt the job.
63 Valiant 225: tiny one from the rear of the engine. Been going on for years. And leaks around the valve cover [ gasket getting replaced even as we speak while the car is in for new motor and trans mounts and new drier and compressor for the aftermarket AC ].
The ION has never leaked in 13 years. So far all looks good.