S3 start up noise

[Scottishdude]

Hi folks my s3’s making strange noise on start up from over night, cold car, does it every time, but after started it’s fine,


Any help would be greatly appreciate, garage can’t determine what it is,

 

[AlS3BE]

Is the air con on? Could be the compressor.

 

[Scottishdude]

Nah the cars air con is off, it very seldom on, it only does it first start of the day, it’s Bizzare, therefore hard to diagnosis

 

[ahtcap]

Alternator Pulley???

 

[Scottishdude]

Kinda hoping it gets worse to be able to get it sorted long term,

 

[Scottishdude]

They said if it was a pulley it would be present nearly all the time, I just need to keep an eye on it, someone might have came across it before, thanks for the ideas though guys, really good community here!

 

[ahtcap]

Pulley is an easy check to rule it out. The alternator works harder when the car is first started especially from cold..

 

[LightRobin]

start it with the alternator belt off, if the noise stops then you can narrow it down to one of the pulleys, if its still there then you can rule out all aux belt driven components
as for whoever said it would be there all the time if it was belt related is wrong, my previous car would make a knocking noise when you rev it in neutral intermittently, after months of faffing around it ended up being the alternator pulley

 

[LightRobin]

it will give you a code and warning on the dash if you do that btw but the battery will let it run for quite a while

 

[ccs3]

Hey mate, did anything come from this?

Mine seems to do it once during start up but that's it.

 

[ccs3]

Hey mate, did anything come from this?

Mine seems to do it once during start up but that's it.

Just to add to this, it doesn’t always do it, seems to be random.
Also, sometimes it will do it once, sometimes it will do it 2-3 times.

 

[nothingness]

The little trumpet noise? Mine does this too, only on cold start, only when it's been raining, and only about 5 times. IIRC the answer I found was when one of the belts is wet.

 

[ccs3]

“

The little trumpet noise? Mine does this too, only on cold start, only when it's been raining, and only about 5 times. IIRC the answer I found was when one of the belts is wet.

Interesting… Funny you mention rain, I’ve had my S3 for a month now and never noticed it until this week when the rain returned.

How long has yours behaved like this? Did you get an answer online or did you take it somewhere to get checked out?

 

[nothingness]

Since about 2 weeks after I bought it, which was during sunny weather. Just found out online, vwvortex or audizine I think.

 

[ccs3]

Came across this post:
https://www.vwvortex.com/threads/weird-“hmm”-noise-on-cold-startup.9300491/

Comment #15 links a video which sounds similar.

seems to be normal

 

[pburv]

Hi folks my s3’s making strange noise on start up from over night, cold car, does it every time, but after started it’s fine,


Any help would be greatly appreciate, garage can’t determine what it is,

Had the same noise from my 2015 S3. Got a bit louder the older it got. Was told it was the secondary air pump on cold start up. From memory I think it,s low down in the engine bay at the front? Was told not to worry about it so I didn,t lol