Help diagnosing rhythmic whirring sound
Help diagnosing rhythmic whirring sound
Author
Discussion

Doodlebug87

Original Poster:

188 posts

144 months

Sunday 22nd March 2015
quotequote all
I've had an annoying rythmic whirring/pulsing sound emitting from the engine bay for quite some time now but it's now starting to grind my gears (not literally). It can be heard from idle and the the frequency increases with RPM, at idle it can be heard probably two or three times per second. This is st enough but when driving I find myself tuning in to the sound and when accelerating it ruins the sound of the engine completely and thus what should be an event turns into a struggle to maintain my sanity. Initial thoughts were aux belt, the pulleys seem to be running true but there is a very slight lateral movement in the belt as it rotates. I have also been over the engine bay with a screwdriver to listen for sounds and potentially the suspect could be the alternator. Unless I am beyond help and have gone mental, the sound I can hear when pressing the screwdriver on the alternator appears to match the rhythm. Can alternators make a pulsing/rhythmic sound? I thought when shot they would generally just sound like a bag of spanners in a washing machine rather than being rhythmic

Here's a short clip, hopefully you can make out the sound, sorry for cack quality

http://youtu.be/ntT39sjqO6Y

Funkycoldribena

7,379 posts

185 months

Sunday 22nd March 2015
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Video doesnt work,and is it an Aygo or a 911,sort of helps a bit...

Doodlebug87

Original Poster:

188 posts

144 months

Sunday 22nd March 2015
quotequote all
Haha yes I should have advised the vehicle in question... Civic Type R (FN2 / 57 plate)... weird, the link works for me

Monkeylegend

29,584 posts

262 months

Sunday 22nd March 2015
quotequote all
Doodlebug87 said:
when accelerating it ruins the sound of the engine completely and thus what should be an event turns into a struggle to maintain my sanity.

http://youtu.be/ntT39sjqO6Y
Must be the Aygo.

Doodlebug87

Original Poster:

188 posts

144 months

Sunday 22nd March 2015
quotequote all
Oh bks what a kerfuffle, I have somehow misplaced a supercharged K20 and replaced it with a 1.0 VVTi without actually realising until now. I thought I was in Vtec but unbeknown to me it turns out I left an open socket set under the cam cover. Someone is having a blast in the worlds most mental Aygo while I'm left with this. Regardless of this situation I still have a fking stupid noise I'd like to eradicate!

Impasse

15,099 posts

272 months

Sunday 22nd March 2015
quotequote all
Doodlebug87 said:
Oh bks what a kerfuffle, I have somehow misplaced a supercharged K20 and replaced it with a 1.0 VVTi without actually realising until now. I thought I was in Vtec but unbeknown to me it turns out I left an open socket set under the cam cover. Someone is having a blast in the worlds most mental Aygo while I'm left with this. Regardless of this situation I still have a fking stupid noise I'd like to eradicate!
Fix this first:


mybrainhurts

90,809 posts

286 months

Sunday 22nd March 2015
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Have you checked under the bonnet for illegal immigrants? They make noises when they're hot.

Doodlebug87

Original Poster:

188 posts

144 months

Monday 23rd March 2015
quotequote all
No immigrants from what I could see and no nuts in the airbox, although I've noticed that whoever changed the crank pulley has replaced it with a wagon wheel. The issue with this is they are much smaller than they used to be so everything is under spinning.

Right, video updated, my fault for being a burke and setting it as private- http://youtu.be/ntT39sjqO6Y

Any thoughts?

Doodlebug87

Original Poster:

188 posts

144 months

Monday 23rd March 2015
quotequote all
Not even any non-useful, comedic suggestions?

mybrainhurts

90,809 posts

286 months

Monday 23rd March 2015
quotequote all
Duff freewheel on the alternator pulley?

lufbramatt

5,695 posts

165 months

Monday 23rd March 2015
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Cambelt tensioner or idler pulley bearing?

mybrainhurts

90,809 posts

286 months

Monday 23rd March 2015
quotequote all
:shudder: