The big ones from the air filter to the turbo and the turbo to the inlet manafold.
Turbo could be passing air past one of these pipes, split, slack etc, but you should see some signs of it coz turbo's all pass a bit of oil so look for traces.
But first take the pipes back from the turbo and look at the blades. They should be nice and smooth with no damage particularilly to the ends of the blades. The turbo impeller will have some movement on it laterly but not enough that it can touch the casing, and it's this which damages the blades, "feathering them" which causes the whistling.
Is it whistling noise you have or one that sounds like an air leak (phssssssssst type sound) on acceleration and lack of power? This could be intercooler hose leaking.
Is it whistling noise you have or one that sounds like an air leak (phssssssssst type sound) on acceleration and lack of power? This could be intercooler hose leaking.
Phssssssssst or phssssooosht or phssssssssssssssssst, or even phut phut phssssssoooosht. heheheh.
Had a workshop controller once who used to describe noises comparing them to musical instruments, i.e, sounds like a trombone, right all I need to do is fook orf and find a trombone now eh. Fokin drove me nuts.
For what its worth, I know I have no problems with turbo etc. on my TD4 (problems elsewhere maybe....) but I can hear tthe turbo whistle, especially with the drivers window down. Same on others I have driven, so might not be a problem?
I can hear my turbo whistle too when window down but apart from that no other problems (yet!)
Glug Glug pass beer!
And workshop managers eh - "I've got this strange grinding noise coming from under the truck I'm driving and oil leaking out on the road. I think its gearbox. We're the mechanics son we'll decide...it'll be ok if there are no warning lights on keep going.....grind bang grind thud clunk sudden stop...err me prop shafts fell off....Oh we best come out no then now T break done...it'll need recovery...I told yer we're mechanics we decide....1 hour later they arrive in a transit....yep its propshaft and will need recovery WELL FOOKING THANKS!