The 'built-in' cooler consists of a kidney bean-shaped 'pellet' integrated to your radiator...it holds less than a half quart of fluid at any time. Even the most basic external oil cooler is a vast improvement, especially when towing in mountains.

You would also do well to assemble a list of independent shops and brickboard members along the way. Dennis' Volvo Repair in Springfield, Mo, for example (ask me how I found out about them :-).

If you attend to all 'the basics' and preventative maintenance on your good tow car, you should be fine.