I've had my engine noise since repeated oil pressure problems. Mechanics have told me there's some clicking coming from the valves and the fuel injectors (normal), and a knock from down inside (bad). I only hear one noise. How do you tell all this apart? How do you know whether it's rods, fuel injectors, valves, or the rubber dampers on the valves? I'm confused. I can hear my noise at idle but it gets louder when under load (before shifting at high speeds). Is THAT the rod knock or still the valves? I can't say if engine temperature plays a role, it seems to do it all the time. Judging from the responses here this problem is not uncommon, although I have yet to come across a Volvo that sounds like mine.