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Doug C.
Doug C., ASE Certified Technician
Category: Volvo
Satisfied Customers: 8652
Experience:  ASE Certified Technician and Volvo enthusiast
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I have a Volvo V40 2002 with an intermitant rattling sound

Customer Question

I have a Volvo V40 2002 with an intermitant rattling sound coming from the engine.Thought it could be cam belt,had a new one put on.still getting the noise but only after the engine has warmed up.Engine management light is also on.The light has had a history of coming on and off for the last couple of years when weather is hot but no noise,not until recently .Any thoughts.Thanks Graham
Submitted: 5 years ago.
Category: Volvo
Expert:  Doug C. replied 5 years ago.

I would be most concerned about an oil pressure issue or valve clearance issue at this point... both are things that will make noise as you describe once the vehicle warms up.
The VVT hub is well known for failure but rarely to make noise, more often to just leak oil... and a lot of it. Further, by the time it does actually make noise it will set a timing retard fault that will not go out on it's own. It is worth noting that if oil pressure drops this is a malfunction location as well since the hub is pressure driven. It is spring loaded though, so a pressure loss will not cause the hub itself to make noise.

If you have no permanent faults I would be looking more at a possible oil pressure issue first, especially considering the potential for further damage if it is in fact the case and you spend too much time on other things before getting to that. Most shops will test your oil pressure for a half hour labor or so; it is not real difficult to access on this engine.

Additionally you can easily isolate any accessory drive issues by removing the ancillary belt when the problem occurs. If the noise still occurs you know it is engine internal. With the belt replaced and hopefully the tensioner and idler, water pump all inspected, that only leaves significant faults (valve clearance, piston slap, oil pressure).

If you find the noise goes away with the ancillary belt removed, go straight to the alternator first... these are common to have the bearings weaken in these and cause an annoying rattle like noise with engine rotation.