Thread: New noise

No clues but I assume that it isn't the serpentine belt? That is a common noise.

Turbo whistles are usually caused by leaks or bearings. You found a leak. It's caused by exhaust gas escaping under pressure when the turbo is on boost. I'd fix that before worrying further.

Sounds like turbo hose as the turbo only really works under load.
ie you won't be able to do it by reving the nuts of it in the garage or while you have you head in the engine bay
Could be the bearings in the turbo , but I am hoping for you it's the hose

Is their lack of power as that will tell you if is the hoses. If not but still Making noise the turbo fan bearings.

Originally Posted by eeyore

Hi everyone,

Just recently my 300tdi has started making a loud whistle / shriek which seems related to turbo boost pressure. It only occurs above 2K rpm, and only under load and with a decent throttle opening (I can't replicate the effect by reving it in the garage for example) . The noise stops immediately if I lift off the throttle. I've checked every hose connection I can find and the only unusual thing I've noticed is the presence of soot below the exhaust manifold on the convex part of of the block casting that accommodates the water pump housing.

Any ideas as to what the likely cause is? The soot suggests a leaking manifold gasket I guess but that may be just a coincidence.

Thanks

if you suspect the manifold gasket, inspect it carefully, you could use soapy water in a spray bottle to see if there any leaks.
mine blew out the manifold gasket which torched the wiring loom to the alternator, which took a bait and had to be replaced, the loom and the alternator, that is.
it also torched the water pump top hose and the bottom radiator hose at the top hose to the manifold.
it was a costly experience, and i was lucky that it happened on home turf.

Thanks to everyone for their help. I'll replace the manifold gasket and hopefully that'll fix the problem - if not, at least it will stop me torching my alternator, loom and radiator hoses! After that, I guess it's the bearings. I _really_ hope it's not the bearings...

Check that the out hose (not exhaust) on the turbo hasn't got a split that you cant see unless you take it off and have a good look, Regards Frank.