Turbo Siren?

[independence73]

Gents! I know only about enough to be dangerous!
My 2006 Navara (I assume D40) has always made a modest turbo whine (especially when cold) when accelerating but it's got quite a bit louder recently. The truck is still running well. When revved hard there is quite a lot of black carbon coming out the exhaust. The turbo noise is like a police siren in the distance. It seems to be coming from the turbo and is most obvious when decelerating, but I think it's always there, you just can't hear it over the engine noise during acceleration. I've read so many posts that warn it's not always the turbo and could be injectors or EGR issues etc. I don't want to spend good money on the wrong part. A mechanic did look at it (very briefly) and said it was the turbo, probably a bearing within it. Do you agree?
As it's quite old, I don't want to throw too much cash at it. Are reconditioned turbos any good? Can you suggest a good reliable company I get one from?

 

[MANNING]

Hey Mate, Welcome to the forum

Not sure I hear anything wrong? Might be me?

After replacing the air intake hoses and putting on a snorkel, it got even louder

It has definetly dulled down with age and with installing a bigger exhaust

 

[Old.Tony]

It doesn't sound terrible - but it would pay for you to check the turbo shaft yourself. Cold engine, pop the intake hose off the turbo, try to wiggle the shaft.

You could also pop one of the outlet hoses off and wipe your finger on the inside, it should come away with a black smear. Examine this smear under a bright light - if you see metallic particles, chances are the turbo is worn.