Turbo Sound after spirited drive

[Aredeth90]

Hi guys,

 

My little 1.2 tsi 110 just developed a temporary turbo and rev dependant sound, something like a very subtle grinding noise, i needed to have the windows up and music off to hear it.

 

So after i drove the car from Worthing to Guildford on B roads, and overtaking everything,10-15 minutes away from the destination i was hearing the slight noise coming from under the bonnet, from 1600-1700 rpm (turbo pick up rpm) and picking up with the increase in rpm.

 

• No power loss, no fault codes.
• 23 degrees outside temp, water was middle, and oil was 95-96 degrees.
• Not a mechanical grind, rough, just a slight metallic woosh
• No sound before the turbo kicks in or at idle.
• Oil was checked, and was at the proper point on the dipstick.
• Overtaking was done using 2nd 3rd and 4th, changing gear at max 4700rpm in 2nd, less for 3rd and obv. even less in 4th, not labouring the engine, not getting over 5000rpm at all.

 

So after getting to the destination, i've let the car idle for a bit, as i usually do, then went to eat.

 

After 1 hour and 10 minutes, engine still warm-ish, started driving towards London (motorway), and the sound persisted for 10-15 minutes into the journey, then it was gone.

 

So now my question to you, what could have been causing it?

Now that the sound is gone, shall i worry? Book a check-up at the dealer?

 

Car is 1.2 Tsi 110 Manual, 4800 miles, factory fluids.

 

 

Regards

 

[13TSI]

It's not this is it:

http://www.briskoda.net/forums/topic/402038-hummingvibrating-noise/#entry4644503

[Aredeth90]

It's not this is it:

http://www.briskoda.net/forums/topic/402038-hummingvibrating-noise/#entry4644503

I just listed to both of the videos from your link, not the same sound.

I would have recorded mine, but it just went away...

[Aredeth90]

Just went yesterday for a 10 mile drive, north London traffic late in the evening, so smooth flowing, max 40 mph.

 

The turbo sound came back at half the distance, and i tried to record it, but it's masked by the engine noise.

Another try at explaining the sound: * a knife gliding across a gritty ceramic plate (cheap Ikea kind), with no pressure, and imagine that relative to speed of the knife...

 

 

I will book a visit to the dealer, better have it checked before we go for a small tour of Europe in less than 2 months, and i'm not looking forward to going bang on the Autobahn.

 

Thanks.

[Ootohere]

Are you sure it is not Disc Brake / Pad noise amplified from the wheel arches towards the under bonnet?

[Aredeth90]

Are you sure it is not Disc Brake / Pad noise amplified from the wheel arches towards the under bonnet?

I had the arches lined with soundproofing material, so not a chance.

 

The thing is, it's rpm related, so the speed doesn't matter as long as i am in the turbo range,but even in free rev i can hear the sound, only from the turbo kick in point, and then the sound increases with RPM.

 

It drives me nuts, especially that the car is really quiet now after the soundproof job.

 

I will listen for it again, as this evening i'm doing an 80 miles trip, most likely the noise will get back...