Turbo noise issue

Hi mate, are you definitely sure its not a boost leak from a split hose or loose clamp? I'd be checking all the hoses from the Turbo - intercooler - intake manifold. If they are all OK it may be a leaking Turbo - manifold or manifold - head gasket. If that's leaking you will need to replace the gaskets.

Try pulling the inlet pipe off the Turbo and have a look inside the housing. Also give the turbine a spin and see if you can hear the noise then its the Turbo. If not then look for a leak.

It's hard to get to the turbocharger compressor wheel on the D40 without some disassembly because they put a joiner on that angles the intake up towards the air box. My fingers are quite long and I don't stand a chance, but then my hands are also rather large, so if you've got smaller hands you might manage it. Giving the turbocharger a twirl is the best indicator of whether the turbo is damaged or not.

However I'm more inclined to think that bods has hit the nail on the head and it's a boost leak. This could happen through accident - like a stick poking the intercooler - or through overtightening the air hoses between the turbocharger and the intake manifold - or lastly through a crack or split in the hose (although yours seems a little young for that, but don't discount it!).

In order to make sure you don't damage your turbocharger bearings, give the turbocharger time to cool a little before shutting down the engine. Once the engine stops, the oil stops flowing through the turbo's bearings and the heat from the turbo will cook the oil, forming hard deposits that eventually damage the bearings. Cooling the turbo is as easy as just driving gently for the last 2-3 minutes before arriving at your destination, or letting the engine idle for 1-2 minutes once you've arrived.

Here's hoping yours is just a minor boost leak!

+1 on boost leak in a hose or gasket. Good luck

With the low km's you have I would think boost leak too but in saying that a couple of guy's in Europe have had turbo bearing failures so could be that also.

Why don't you get someone to rev the engine while you've got your head under the bonnet and see if you can pin point where the noise is coming from.

My D22 makes the same whine and I only really notice it when I am driving slowly. I'm not convinced its the turbo but havn't been able to locate it. It does sound like a police siren is on the road in the distance. The whine in my D22 occurs at lo revs which makes me think it not related to turbo.

Dont think i would be a boost leak. Normally if it sounds like a police siren then the turbo is on its way out and will probably need to be rebuilt. with such low k's it should still be under warranty, I'd get it checked out.

Thanks for the advice guys

I did check the turbo for leaks and found none, however I will look into the boost leaks and check the compressor wheel. The vehicle has no turbo timer and I am now wishing that I should have installed one earlier.

I'll keep you all in the loop !

Checked with my mechanic today and he said it's definitely not a turbo bearing problem but a boost leak problem.

Taking the Nav in for repair next few days.

Will let you know how it goes.

Blackbyrd said:

Checked with my mechanic today and he said it's definitely not a turbo bearing problem but a boost leak problem.

Taking the Nav in for repair next few days.

Will let you know how it goes.

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Please keep us informed of your progress. I would love to get to the bottom of my "siren"!

Had it checked today and it's not a boost leak, It's the Journal Bearing in the turbo that's faulty. I understand it can't be repaired so it has to be changed.

I'll try to see if it will be covered under warranty

It's pretty early (31,000km) to have a turbo bearing failure. Do you let the engine idle after driving the car on the highway, or do you just shut it down like a petrol car?

Hi everyone, very new here.
Wanted to know if anyone has had any luck solving this issue? My D40 is making a squealing noise when i put my foot down, then it stops once the revs are below ~2000 from memory.
Sounds like an old kettle whistle. Nissan hasn't been able to help (no pipe leaks) and I don't have any mechanic mates to give me a proper answer.

Mine did that when the gasket between the turbo and the exhaust manifold started to leak. Look for soot around that area, mine was fairly obvious (once you knew where to look).

Thanks very much mate, will have a look tomorrow and see if I can find anything. Something I can tighten up?
Only started happening after I had a cracked header (major eff up by the mechanic).

If it's been squealing for a while you'll find that the gasket has deteriorated from the vibration so it won't just be a tighten up. One of the studs in mine had come loose too, and another had siezed - glad it was someone else's problem (my mechanic)!