I only have experience of one Volvo. My P80. Now clear of 320,000 miles with gas. It's getting very clunky but still goes. It's a factory Necam job. These have iissues, but I've always managed to cobble it up to keep it going.
These cars are found rust-free even at 20 years old. They go forever. Follow these pointers and you'll see much the same:
https://www.volvoforums.org.uk/showthread.php?t=263883