The procedures for replacing the seals for the turbo return line are the same as on the 850 and S/V/C 70. The problem with the XC models is that there is a front differential in the way. The new O ring seal is green in color, so don't let anyone sell you the old orange colored ones. The newer green ones are a different compound and last longer before deforming enough to allow oil to leak out. You also need the green paper gasket that is behind the 30torx screws. Note I said 30 torx screws, most of the other cars have a hex bolt but for some reason Volvo has decided to make these 30 torx screws/bolts. I use a ¼ with a swivel for the front bolt and the back one is a lot easier, and no swivel is needed, although a long extension is also needed. Notice the coolant pipe to the turbo just above the green arrow, that might get in the way, don't be afraid to gently pry it to give you the ability to get the tube out once the torx screws are removed. A 17mm banjo bolt is what holds the coolant line to the turbo, you might have to give it a ¼ turn to tighten it if you gently pry it out of the way.

There is a bracket that holds the turbo return line pipe to another pipe to give it stability, that clamp is held in place with a 10 mm bolt and nut. To get the clamp off you will need to have patients and reach up on the top of the front differential and with small wrenches or a small ¼ ratchet get the bracket off. I don't take the nut and bolt off all the way on the bracket, almost all the way but not quite, then I rotate one of the clamps 90 degrees and lift the entire mess out as one piece. Once the 30 torx screws are off and the bracket is removed you can wiggle the return pipe out of the block. If when you get the pipe out the O ring is not on the pipe, it will still be in the block. Use your little finger in the hole to remove the old O ring. When you are trying to work the pipe with the new O ring backing the block a little bit of lube or seal glide will help get it seated in the hole correctly. I gently tack the top green gasket to the turbo return line and let it dry in place, then I don't have to worry about getting the top green gasket into place once the pipe is in.

Just one more picture to show you an up close view of the top part of the Return line pipe where it bolts to the bottom of the turbo with 30 torx screws. After everything is back in place, I use brake clean to clean everything up so I can detect a leak in the future.