I didn't use any sealant when I replaced mine. I don't know what that would be used for. I didn't encounter any sealant when I removed everything, so why would I need any to put anything back?

As far as compressing the tensioner, a c clamp will work, but perhaps a bench vise would be safer. And yes, you must do it slowly. I spent about 7 or 8 minutes doing mine, slow turn by slow turn. You don't want to blow those internal seals. :)

On a side note, some volvo designs leave me guessing as to what they were thinking. The timing cover, however, is a WONDERFUL design. You remove one bolt and the entire cover lifts right out. Genius! I build Toyota Camry and Avalon V6 engines and the timing covers on those are NOT intended to be user serviceable. It's a two-section cover. The top section is held on with about 8 tiny bolts. The bottom small section is behind the crank pulley, so you have to remove it before you can even take the cover off and remove the timing belt! What a horrible design.

kevin