First, you need a set of ramps or tall jack stands. The radiator comes out of the bottom. Most of us use Nissen and never bother with the drain valve anyway. Just drain it by taking off the bottom hose with a 2 gallon catch pan.
Get new bottom and top hoses for piece of mind.
When removing the old radiator, save all of the attached bits on the side and transfer them to the new radiator.

Also look at Volvospeed and Matthews for pics and helpful hints.

Don't over tighten the new hose clamps! You will crack the plastic connecting necks on the new radiator, snug is good. And snug means the hose will not twist on the plastic neck by hand.

Klaus
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Proud owner of a 220S. If I had more room, I would have more Volvos.

For a driveway do-it-yourselfer, I would rate this job a 7 out of 10 on the PITA scale. I would recomend a BEHR radiator because the drain valve on the bottom is much nicer than the Nissens plastic screw. The BEHR is 224.00. Free shipping on many sites.

Problems:

You take the top cap off that holds the egr vacuum lines- remember where they go.

The 3 little phillips screws that hold the electric fan to the radiator are tricky.

The Bolts that secure the bottom of the radiator run through nuts that are welded in place. The welds brake and you need another person to help get them out.

If you replace the lower and upper hose as well, you will need to remove the air filter box and anything else in the way. The plastic clamps that hold the lower hose are secured all over the place and take a while to get out.

I would start by taking PB Blaster to every screw and bolt you can see.....
The job took me an entire Saturday on a nice sunny warm day.

Seems like it would not be too bad - I have not replaced the rad but did the starter motor on my S70, and that involved taking out most of the same parts except the rad itself. Do you have Haynes?