I have a late 93 Lightning (w Trailer Tow Package which may have an effect on this problem as I'm not sure all Lightnings have the same setup).
The lower radiator hose is one piece with the Heat Exchanger from the Oil Cooler and is also one piece with the dual lines that connect to the sandwiched Oil Cooler between the Oil Filter and Filter/Cooler.
In short when you care to replace the lower Radiator Hose you are buying a new oil cooler with the hose perminantly attached to connect to the water pump as one piece..... and pricey at like $110.
Any alternatives?

 

I just replaced the section from the cooler to the radiator; it looks like the section with the cooler integral to it will last a lot longer.

 

If you are faced with the prospect of spending that much money, consider this: Change to an external oil cooler & remote oil filter mount. You will probably save some $ & have a better cooler setup besides. Using a remote filter setup will also make changing filters easier & less messy, since the stock setup means your truck pees oil on itself each time you change the filter. Mount your remote filter setup in a location that will allow it to be vertical & you will be able to get more oil into the new filter when changing your oil, thus minimizing the dry time with your initial start up after changing the oil.

Replace that lower radiator hose with one designed for the non-oil cooler application & remember that you will also need to change from the FL-820S filter to the FL-1A (or equivalent).

dn.