I looked at the usual sites and could not find any good tutorials.
a couple of them have you removing the coolant tubes at the firewall, which I do not suggest.

The following link is a pain because of the Photobucket approach, but it is the correct way to repl the core. I suggest using a plastic shopping bag to collect spilling more antifreeze inside the car. You can also use vice grips(2) to squeeze the hoses closed between the engine and firewall, so you don't have to 'drain' the system. There is about 1/2 quart of coolant in the core at all times.

www.volvo-forums.com/t22870-1998-volvo-v70-heater-core-replacement-w-pics.htm

You will need the O rings for the coolant pipes at the core. Don't forget the torx screw that holds the pipes to the core!

Klaus
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