If you ordered the trailer tow package 2004& up you'll have these engine oil cooler lines to the cooler located by what the oil filter attaches to. There's two parts, the upper section noted to rot out, is $108 CDN. The lower section with the cooler and much shorter line sections you could probably get reworked is $500CDN. I'd suggest replacing the upper section with the thermostat when you do you coolant change. Treat the lower section always with corrsion inhibitor like rust check to keep it under control. It's easier to access of you ever have to change it anyway.

After following my advice and changing this line. It was difficult getting this upper line out because of a single bracket welded to the metal lines, so i bent it out of the way. On the new one, i removed it before install, and tie-wrapped it together after install. An alternative fix would have been to remove the oil/water cooler line assembly, not install a new one, and reconnect remaining coolant line as this added cooler just opens and existing connection point on the basic Freestar.