Oscillating hum/ from inside the cabin

[PodDogSki]

Purchased a Cupra 290 ST last October from a Franchise dealer and on my drive home noticed a deep hum or drone noise at 75-80mph that seemed to be coming from inside the cabin. The hum goes loud and quit in one second intervals. I tried changing driving mode to comfort, sport and cupra and the sound is still there. I've recently rotated the tyres, had all 4 wheels balanced and also had the tracking done, still having the same problem. The sound is more noticeable when going up a hill and is less noticeable when turning the wheel slightly. Got the car booked in under warranty with the after sales manager next week.
Anyone got any ideas of what the after sales manager might say/do. Anyone had any experience of this. I'm not feeling too confident that they'll be able to diagnose the problem.

 

[Mr Pig]

I could be a bad tyre.

I had this exact symptom years ago. I thought it was a wheel bearing but eventually I discovered that the noise moved when I rotated the tyres. Turned out to be a tyre with a twisted carcass. You couldn't see it with the naked eye, balancing made no difference.

If it's a tyre or wheel bearing you can find it like this:

If the noise gets louder going up hill it's at the back.
If the noise gets louder going down hill it's at the front.
If the noise gets louder turning left it's the right wheel.
If the noise gets louder turning right it's the left wheel.

Basically, loading up the bad wheel makes it louder. Once you figure out which wheel is the problem, swap that wheel to the opposite corner. If the noise follows it, probably a bad tyre. If the noise stays where it is, probably a bad wheel bearing.

Also, if the car is a few years old and the rear suspension is a bit worn and out of alignment it can cause 'cupping' on the rear tyres. This will also cause a drone. If you feel the tread on the tyres, probably mostly on the inside edge, you will feel alternating lumps and hollows as you go around the wheel.

Obviously there could be other issues causing a drone but these are the more likely and the first things you want to check.

 

[Cuprabenwytm]

I also have this noise in my 290 and from what a can read its something at the nack resonating, you can buy a weight that instals on the rear sunframe that supposed to stop it but iv just got used to it now, does it sound like a tree rolling

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[Cuprabenwytm]

How to retro-fit the rear subframe harmonic damper from the Audi A3 Saloon (2013->)

Disclaimer:- This info is for community usage. I am NOT affiliated to, or sponsored by, any company/individual to promote them or their products. Companies/individuals may NOT use my name, photos, or threads/technical guides, for financial or personal gain (fraudulent misrepresentation). Part...

www.golfmk7.com

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[PodDogSki]

How to retro-fit the rear subframe harmonic damper from the Audi A3 Saloon (2013->)

Disclaimer:- This info is for community usage. I am NOT affiliated to, or sponsored by, any company/individual to promote them or their products. Companies/individuals may NOT use my name, photos, or threads/technical guides, for financial or personal gain (fraudulent misrepresentation). Part...

www.golfmk7.com

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Thanks for this - i will suggest this to the dealer for sure see if they will fit it for me under the warranty. SEAT must know about this issue.

 

[Cuprabenwytm]

No problem friend, let us know what they say please

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[PodDogSki]

I could be a bad tyre.

I had this exact symptom years ago. I thought it was a wheel bearing but eventually I discovered that the noise moved when I rotated the tyres. Turned out to be a tyre with a twisted carcass. You couldn't see it with the naked eye, balancing made no difference.

If it's a tyre or wheel bearing you can find it like this:

If the noise gets louder going up hill it's at the back.
If the noise gets louder going down hill it's at the front.
If the noise gets louder turning left it's the right wheel.
If the noise gets louder turning right it's the left wheel.

Basically, loading up the bad wheel makes it louder. Once you figure out which wheel is the problem, swap that wheel to the opposite corner. If the noise follows it, probably a bad tyre. If the noise stays where it is, probably a bad wheel bearing.

Also, if the car is a few years old and the rear suspension is a bit worn and out of alignment it can cause 'cupping' on the rear tyres. This will also cause a drone. If you feel the tread on the tyres, probably mostly on the inside edge, you will feel alternating lumps and hollows as you go around the wheel.

Obviously there could be other issues causing a drone but these are the more likely and the first things you want to check.

Thanks for your help, I hope the mechanic who will try and diagnoses the fault knows what they are doing, I was expecting to be told I need new tyres as its the most obvious solution & probably a less costly option for the garage as tyres are not covered by the warranty. I see there may be a part that i can get fitted that might also help.

 

[PodDogSki]

No problem friend, let us know what they say please

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Booked in on the 15/02/2021 - after sales manager booked it in for 2 days!

 

[Mr Pig]

Thanks for this - i will suggest this to the dealer for sure see if they will fit it for me under the warranty. SEAT must know about this issue.

I'm sure there are many things Seat know about. Knowing about them, admitting they know about them and doing anything about them are three very different things.

 

[SuperV8]

Thanks for this - i will suggest this to the dealer for sure see if they will fit it for me under the warranty. SEAT must know about this issue.

I think my car has this 'trait' as well. A rhythmic noise that above 70mph, and seems worse on rougher roads.

This damper has only ever being applicated on Audi A3 saloon - so I really can't see Seat fitting one under warranty for you i'm afraid! - but if you don't ask...

 

[PodDogSki]

I think my car has this 'trait' as well. A rhythmic noise that above 70mph, and seems worse on rougher roads.

This damper has only ever being applicated on Audi A3 saloon - so I really can't see Seat fitting one under warranty for you i'm afraid! - but if you don't ask...

I guessed that the warranty will not cover a part never fitted to the car in the factory - so i've purchased the part from https://www.allcarpartsfast.co.uk/ and hope that they will fit it for me when it goes up on the ramp. Again I'm not getting my hopes up that they will do this for free. If I have to pay then so be it. It will be interesting to see what they suggest first of course and then bring the harmonic damper into the conversation and see if they can do a "gesture of goodwill"

 

[Mr Pig]

I hope that they will fit it for me when it goes up on the ramp.

It's two bolts. If they won't fit it free just do it yourself.

 

[Cuprabenwytm]

You can buy it for about 70 quid i think

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[PodDogSki]

It's two bolts. If they won't fit it free just do it yourself.

I need to purchase a torque wrench - it can't be that difficult to although it does look a bit tight getting the tools next to the exhaust backbox & pipe

 

[PodDogSki]

You can buy it for about 70 quid i think

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I paid £72.76 with FedEx/UPS delivery & that includes the 2 nuts for the bolts

 

[Mr Pig]

I need to purchase a torque wrench..

Naa, it's just a weight. Good and tight and it'll be fine.

 

[Cuprabenwytm]

As the fitter at work says the torque setting is ft, f***ing tight haha

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[Cuprabenwytm]

How has the weight held up did it work

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[PodDogSki]

So I got to use my new torque wrench, fitted the part myself took about 5 mins. It has made a difference to noise from bumps and potholes at low speed with a noticeable difference to the hum at high speed, I thought it had sorted the problem until I quickly manoeuvred from lane 3 to lane 1 at high speed and the sound became clear again! However on taking the car to SEAT they have identified a slight buckle in the off side front wheel! The wheels were rotated about 6 weeks ago when I first noticed the noise so the original position was nearside rear. Rotating the wheels didn't make any difference to the noise. SEAT have booked me in Saturday and are refurbishing the wheels for me. When I purchased the car the wheels were sent off and refurbished at a place in Sheffield. SEAT are saying one of the wheels was probably not done correctly so will sort the issue under warranty. Hopefully that will fix the rhythmic humming noise. They say it should take about 5 days to sort.

 

[PodDogSki]

I think the torque setting makes a difference, I fitted it without a torque wrench the day before and just guessed, went out for a drive and didn't notice much of a difference. The next day the wrench arrived from Amazon and I checked how tight the bolts were and I ended up having to loosen them to 18nm. Went out for another drive and noticed the difference right away. The part has a rubber centre that may need time to become supple to absorb the vibrations, maybe the rubber was touching the frame, or too tight to absorb vibration correctly.