Just wanted to chime in on the actual recommended oil for your engine.
There was a lot of confusion after Volvo discontinued their straight 30 syn oil. At first the seemingly clear message was that now Volvos 10w-40 was the recommended oil for all engines, but Volvo and its dealers seemed to be sending mixed messages. Manuals saying one thing, dealers and Volvo customer support all having various statements.
I have a 1999 5.0 Gi. I did a lot of research into it and called Volvo to get better clarification on the matter, because my concern was that Volvo's 10w-40 was designed for their post catalytic engines produced from 2008 and on. Mind you those engines, beyond just the emissions equipment, are based on a completely different generation of GM small block than our engines.
What I ended up finding was a Volvo technical bulletin that specially stated that the following:
All 2008 and newer engines were to switch to Volvos 10w-40
All gasoline engines prior to 2008 were to use Volvo's VDS-3 Oil (Which is Volvos diesel specification, 15w40)
This would mean Oils such as, Rotella 15w40, Delo 15w40, Volvos own 15w40 etc are now the recommended spec also, also some have used Rosella Syn t6 5w40. I personally use Rosella 15w40. Another oil I would consider is Mobil 1 Syn15w-50.
Here is the link to the bulletin, see page two:
