Does it replicate when you rev in neutral or just with gear on? Have you tested to see if it’s only in certain gear(s) or all? Is it limited to parts of rev range or all across?

 

I've never managed to get it to do it in neutral although I haven't spent a lot of time testing it because it's not every time you rev it happens.. I'll have to use the paddles to quote gears as I normally drive full auto but more often than not it's when you accelerate hard and very infrequent when your just going on the gas.. so a 85/15 split in favour of hard.. Coming to think about it, it's not happening in the first 3 gears but the box is so close it could be 4 or 5 onwards, never pulling out of junction from stationary. Had it the other day and it sound like a ratchet type noise, short burst whilst on the gas like opening a crock lock if you remember them.

 

Update: Ok so I've narrowed this sound down to correspond when the engine is developing maximum boost pulling the car from 1500rpm upto about 2750 - 3000rpm in gears 3 thru to 7. I invested in MES and done the data logging and the rpm and max boost intersect at the point the noise starts. I posted over on the USA forum and got some responses and one of the guys who knows turbos sorted of talked me through taking the intake off etc to check if there was any play on the cold side of the shaft.. There wasn't any play so it's still not obvious what causes this noise. I managed to record what happens from the engine bay and you can hear the rattling very easily and obviously sounds different to what I'm hearing in the cabin. I can get this noise to occur in the N and D modes but can't get it to do it in the A mode.. I might do another data capture in the A mode as I suspect it won't generate the same level of boost.. After spending a few weeks reading about turbos from scratch the only thing I can think it might be is the wastegate clattering but I really don't have a clue.. It sounds like an expensive problem though.. any thoughts appreciated. Cheers

 

It sounds like a vibration within the turbo impeller shaft - the shaft that joins the two rotating parts of the turbo.

Possible causes could be slight damage to one of the blades of the turbine or impeller blades, usually the impeller. Another cause could be some wear in the shaft bearings, causing it to run misaligned.

Given the speeds the shaft rotates, any slight imbalance or play could cause it.

You said you checked the play in the shaft, was there absolutely no play at all, as this would be bad. There should be a tiny amount of movement.

 

I took the intake off and managed to reach the fan.. there was maybe 1.5mm - 2mm play along the shaft push/pull and not really any play side to side.. Once you get through the 3000rpm and max boost it doesn't make any noise at all.. Cheers

 

1.5-2mm of play does seem a little much. What do the impeller blades look like, is there any damage or bent tips?

 

On the cold side the impeller looks perfect, the play is difficult to measure, it's not the easiest thing to grab hold of but I can feel a slight movement..

 

The blades seem to look fine, there's no evidence i can see of bent tips, or damage, nor any oil, which is indicative of a worn shaft bearing. can you grab it with some long-nose pliers?

 

I'll try and find some time to take all the intake off again, from what I've been told, there should be a small bit of play along the shaft but none up and down.. at some point in the near future i'm taking to my local specialist to have all the exhaust bolts and fixings checked they're tight.. it has also been suggested that under pressure some of the gaskets could leak causing vibration. There's no smoke or reduced mpg either.. driving around without pushing it the engine is very smooth..

 

Correct, a little in and out is good, but nothing up/down or side to side. 1.5-2mm in/out is a bit much though.

Its also true a badly fit gasket can cause similar noises - especially metal gaskets! I have had a Zafira with a bolt missing from the intake piping, and 2 vehicles, (t5 transporter and a transit connect) with bolts broken on the exhaust manifold causing a noise akin to a dying rodent, especially at full boost

 

Thanks for your input... whatever the problem is it's also causing some level of vibration as seen in the video, although not felt in the cabin, the camera was crudely mounted on the inner wing with duct tape and you can see the fluttering of the image at the same time the noise occurs..

 

My Stelvio does something a lot like this. A noise on acceleration like a steel ruler being twanged and moved up in pitch. I never investigated this in any depth. I reckon that it is something vibrating in the back of the dash. Only happens when you put your foot down but I always assumed that the acceleration causes vibration which reflects in the plastics in the back of the dash. Of late I now have a second vibration mirroring the first one. I still think its is a vibration inside the car. If the turbo finally explodes, oh well so be it. I don't reckon the turbo is at fault I feel that it is more superficial than that. Part of Alfa ownership is developing the shrug. I certainly ain't spending a shed load of money investigating a maybe, when I am completely content that there is nothing of consequence to see here.

 

I had exactly the same thoughts about the dash until I strapped a phone onto the inside of the wing to record it.. it sounds much worse from the engine bay.. It could still be vibration but it's related to the boost, I can't get it do it in the A mode at all no matter how hard I try but in N & D it can be recreated at will? It seems to be quite rare, not one of the "don't worry they all do it type of sounds"

 

I had exactly the same thoughts about the dash until I strapped a phone onto the inside of the wing to record it.. it sounds much worse from the engine bay.. It could still be vibration but it's related to the boost, I can get it do it in the A mode at all no matter how hard I try but in N & D it can be recreated at will? It seems to be quite rare, not one of the "don't worry they all do it type of sounds"

If yours does it and mine does it perhaps it is not so rare after all. If however it seems that your turbo is about to self destruct please let us know. Mine started to make the noise at quite a modest mileage therefore suggesting it is not a wear and tear fault. Still, I just hope that it keeps on doing it. Perhaps the turbo blades are going supersonic now that they have worn in, the acceleration remains brisk even with the noise happening.

 

Hey guys did you end up finding out what that chirping sound is it’s driving me nuts.

 

No haven't got it sorted, it's still there same as it was when it started about 18 months ago.. tried to get the heatshield off to check the bolts connecting the turbo to the manifold but it needs a cooling pipe to be removed which is blocking access at the back near the bulkhead.. gave up in the interest of time and all the hassle of fluids being drained.. some have reported it's not the bolts holding the turbo, my thoughts it's probably the wastegate rattling around at full boost although have the issue at 1.5k rpm ? I think the turbo needs to come out to look at this properly.. I emailed Garrett who make these units but didn't get a reply about a replacement.. want to source one so my independent alfa garage can tackle it.. from what I could see of the part numbers there have been many iterations of the same turbo so i'm wondering if it's an early model issue.. mines a 2018 registered vehicle built late 2017.

 

Be interesting to do a poll of Stelvio owners to see how widespread an issue this is. Mine started doing the noise a while ago as stated in a previous entry. Still doing in now just the same. I am still minded to shrug. If the noise has remained, unchanged, for so long, and with increasing mileage I'm guessing that it ain't progressive. If yours has been doing it for 18 months I guess yours ain't progressive either. Perhaps they all do it just nobody has mentioned it. I certainly would not contemplate disconnecting a load of stuff to explore the issue and causing a genuine and potentially expensive problem for a possibly modest return. I am more bemused by the smell of burnt feathers I get in the car when I boot it, as the insulation under the bonnet lid heats up. Still does that too.

 

Sadly I have the same noise in my Giulia Comp 2023. I heard it first at 20k km. Now at 25k km. It happens very randomly, under load. And very rarely.

I thought there is something loose in the engine bay and a certain engine vibration causes it to rattle.

Haven't observed any other symptom.

 

So roughly just over a year since my last post on this and it's still making the noise, the only thing that has changed is that it now happens very lightly in the A mode which it didn't do no matter how hard I tried which leads me to assume the problem is getting worse.. Problem I now have is trying to decide how I get this fixed.. I think I need a new turbo but who do you trust to complete the work? A main dealer, an independent or a turbo specialist company. Does anyone have any experience with a turbo swap out in the UK.. from what I've read you may need a new PCM as well as a turbo as well as access to Witech and some codes that need to entered into the ECU etc.. I'm prepared to pay once and get this fixed but need to know whoever does it fully understands the process and has some experience in this line of work..

 

Did you ever check the wastegate rod for the possible cause? I see it mentioned a bunch of times.

Mine seems to have a play but I don't know if it's normal?