HIDDEN DANGER: DO THIS CHECK NOW! Rear Bumper brackets 6816114
I could swear I've posted this before... rear bumper brackets. At the age these cars are at, I've not seen a car without these at dangerous levels of corrosion. I will almost guarantee your rear bumper is set to fall off.
Part 6816114 is a thin bracket exposed to rot. A swift kick and my bumper fell away. Mine should not have passed its MOT. It did because the problem hides well.
Second post down, here's an example of what you'll find...
https://www.volvoforums.org.uk/showthread.php?t=318127
The genuine Volvo parts are cheap. On the bay of E, under £40 for two. get 'em whilst they're hot.