Hey Phil,
I wouldn't worry too much mate. It's the exact same engine as the Frontera 3.2 (I haven't heard of too many of them failing) ...It's as reliable as any engine out there if it's looked after... Oil seems to be the main issue... just keep an eye on the level... and change it preferably before its due.I also asked over on the Frontera owners group if anyone had an issue like this... I can't see anyone who has ...maybe it's just related to the 3.5?.... Were the U.S. models assembled in the U.S. or Japan?