VNT turbo squeal (GT2260V)

[hotrodjacko]

Hi all,

So I've got a 330d with the later Euro4 M57TU engine. It has a GT2260V turbo (standard fitment). The car has been remapped for a few years, prior to my ownership. From memory the last 80k miles have been remapped. Current mileage is 160k.

I've recently had a turbo squeal, when warm, between about 2000-2400 rpm at light load. It almost sounded like a boost leak, but I'm thinking its a turbo failure.

The noise is more like a squeal than a whistle, and once the engine gets to 2500rpm it goes away. I'm thinking its to do with the air flow at the lower speeds causing a larger loading on the turbine, thus causing more load on the failing bearings.

I've had a feel of the shaft, there is minimal axial play (end float) but some movement radially. I wouldn't say its particularly excessive, but it is a fair bit (it's not new, and has covered 160k miles).

Thanks,
Ross

[bashbarnard]

Can you get a video of the noise so we can see? Bit shooty in the dark otherwise


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[hotrodjacko]

Sure, I'll try and get one on the way home this afternoon.

[Danny Wideboy]

Check exhaust manifold for leaks before going too far.
Same symptoms as slight exhaust manifold leak on a T.D. Possible gasket issue.
Check the cheaper option first no?

[hotrodjacko]

https://youtu.be/TH5TO16Uiv8

See link above.

Good idea Danny, I'll check for exhaust leaks.

It's weird, if you listen to the video you'll hear it but after 2.5/2.6k rpm it turns off?! If i have the throttle at say 5%, it'll go slowly through the revs, into the squeal zone, then once it comes out of the squeal the rate of change of the revs increases (i.e. it pulls through to the red line faster of its own accord almost).

Hoping, worst case anyway, that the nozzles haven't burnt out. If it's a knackered bearing, I'll just buy a new cartridge assembly/CHRA and swap the housings over. If it's damaged nozzles obviously I don't have that luxury.

[bashbarnard]

Id say boost leak or exhaust gas leak not turbo with that noise. See what others say as well on here. They may have a diffrent suggestion

[Seb_Ryan]

Same turbo as on my alfa 156 2.4.. Changed it twice. Made hissing/screeching noises when hitting full boost for a few weeks then as soon as it started spooling.. Changed them then and always found intercooler full of oil lol

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[Poodle]

Id say boost leak or exhaust gas leak not turbo with that noise. See what others say as well on here. They may have a diffrent suggestion

This. Have a look for black marks around the exhaust side of the engine bay, particularly stuff like egr.

[hotrodjacko]

Thanks for the advice all.

I'l look into both intake and exhaust bits - I changed the main thermostat recently (it was doing this before that) and didn't see any noticeable smoke marks whilst I was in there (I had a look at the turbo whilst I had the thing in bits). Will check more thoroughly this time - hopefully get a chance at the weekend.

[zx_volcane]

jsut pull the inlet off the turbo - check for oil / shaft play / signs of compressor making contact with housing

[hotrodjacko]

Had a look at that already. No noticeable scoring in the housing, some radial play though but it is without oil pressure. Some axial play but not loads.

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[hotrodjacko]

So thinking about this a bit more. I've not noticed any loss in power, and it only does it when warm. Based on that, I'm thinking it's more likely an exhaust leak, if it is a leak, than boost (warm exhaust expands the crack/gap, leaks out and squeals)

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[Danny Wideboy]

It's the exact same symptoms my pajero has.
I know it's the exhaust manifold on mine because I've seen the carbon deposit around it.
I really should fix it. :-)

[hotrodjacko]

So I know it's a month since I asked but I've only just got round to looking properly. Disconnecting the vac hose to the vnt cures it, so I'm thinking potential small boost leak, or something more broken... Not noticed any soot in the exhaust area.

[hotrodjacko]

So, a couple more videos. First one is the same as the original video I posted.

https://youtu.be/k9ZvtImf6YU

And then after removing the boost hose that comes from the turbo and into the intercooler.

https://youtu.be/NTc51kaqk_w

Thoughts?

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[Poodle]

I think you're going to have to look at that exhaust properly, bitch to get to though it is. The volume doesn't seem to be any different between the two vids, if the compressor/turbine were touching then it would scream with the intake open to atmosphere. Definitely isn't a boost leak since it's the same with the boost pipes off. The noise happens when the vanes are going to be closed up, ie when exhaust mani pressure is highest, so have a good look at every connection upstream of the turbo. A mirror and a good work lamp are your new best friends lol.

[n0v0s]

Sorted this yet? The exhaust manifold is stainless steel on the m57n engines. They're nearly always cracked a bit. So definitely check your manifold ?
My turbo has minimal/no radial play, but a bit too much axial play for my liking. Same as how you describe. I suspect mine is nearly done for. Slight screech/whistle at higher rpm and full boost... So perhaps that's just a separate issue looming soon. My exhaust manifold is also cracked. Joy.