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Discussion Starter · #1 ·
Ok so after one of our mechanics has replaced the cylinder head on a l200 2.5 td it has caused the turbo to whistle, wasn't there before the head job was done. Anything to look for? Vac pipe the wrong way round or a hose not on properly?

Premium Member
3,844 Posts
no much internet information about turbo whistle for a diesel

this information lists things you can look at yourself

if you cant see a cause and fix yourself > next a turbo specialist

What causes turbo whistle?
Turbo whistle is the sound of the compressor inside the turbocharger speeding up (also known as ‘spooling up’, which is why it kicks in at the boost threshold (when the turbo starts to kick in) as you accelerate up the rev range.

When should you be concerned?
All turbochargers make some amount of noise – and most people don’t even notice it. However, if the whistling sound gets louder, more noticeable, or changes in any way, it could be symptomatic of a number of different problems, that all warrant further investigation.

Potential causes of turbo noise include:

• Boost/air/vacuum leak – either on your engine intake, or your intercooler
• Compressor wheel damage
• Split hoses
• Over boosting (potentially caused by a wastegate fault) or poor remap

Thankfully, these problems are rarely terminal, and can be repaired/resolved by a competent turbo specialist.

Other causes of whistling noise

A whistling noise coming from your vehicle can also have a number of other causes, including:

• Exhaust gasket vibration – as parts become loose and rub against each other, they can create a buzzing noise that’s reminiscent of a turbo whistle
• Exhaust gasket leak – the noise could be the exhaust gases leaking through a gap or tear, which needs to be repaired
• Alternator belt slipping or overworking – you may need to have the belt refitted belt, inspect the electrics on your alternator, or change your car battery
• Excessive wind noise – often caused when a window, windscreen or sunroof seal begins to fail
• Air con/fan belt slipping

Whatever the cause, it’s sensible to have it checked out by a reputable mechanic as soon as you can – the noise isn’t going to get any better on its own, and the longer you leave it, the more serious (and expensive) the problem is likely to be.
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