Noise. Any ideas?

steve@cromford

steve@cromford

A2OC Donor
After driving back from N Yorks Dales (great snow over the weekend!) my car has developed a metallic "Pinking" sound from the engine area. I initially thought DMF (which was only replaced 30k miles ago) but it seems to be coming from the drivers side near the cambelt area. It goes quiet when gently revved.
Any ideas?
Regards
Steve
 
Hi i would say it could be the alternator pulley thats making the noise. They have a one way bearing that wears out and starts to slip, If you catch it quick you can just change the pulley but if left it can weld itself to the alternator shaft or worse shear it off ! its possible to test it by taking the belt off and spinning it over both ways-one way will turn the alternator one way won't.
Filing that have a look at the heat shield below the turbo as the mounting holes wear and the vibes cause it to clutter.
good luck mike
 
a2sumo said:
Hi i would say it could be the alternator pulley thats making the noise. They have a one way bearing that wears out and starts to slip, If you catch it quick you can just change the pulley but if left it can weld itself to the alternator shaft or worse shear it off ! its possible to test it by taking the belt off and spinning it over both ways-one way will turn the alternator one way won't.
Filing that have a look at the heat shield below the turbo as the mounting holes wear and the vibes cause it to clutter.
good luck mike
Click to expand...

Hi Mike,
Sorry to be dense. Do you mean spin the sprocket on the alternator pulley to test it? Is a fail if you can spin it both ways as it means the bearing has failed? or is a no-spin a fail? Or is it grinding to look for?

I’m not sure what ‘pinking’ refers to (ironically) but I have an almost squeaking when the engine is warm and below 1000 rpm - stops as soon as you rev over 1000rpm.

If anyone is better at describing noises please jump in. I put a video on YouTube but you can’t really make it out. Seemed to be coming from the off-side of the engine but I need to investigate.

How much was a replacement if you don’t mind me asking?


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Hi
The garage described it as "chirping" which is probably more accurate.
The part was about £50 and £70 for fitting, inc the dreaded VAT!
Regards
Steve
 
Thanks Steve.

Very very much appreciated. Yes - a rhythmic ‘chirping’ would certainly fit!


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Squeaking may mean a loose belt also. Could just be a case of re-tightening or maybe a new belt
 
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Note, I believe it us only the tdi's that have the clutch pulley. The chirping is a good indicator of a failing pulley (tension is controlled by the spring loaded tension roller so no adjustment possible). Whilst A2sumo's advice is good, to test the pulley by seeing if it spins the alternator one way and free wheels the other. Even if it seems ok by hand under load it could still be slipping, causing the 'chirping' noise. This is what happend to me, causing the additional symptom of little or no output from the alternator and the battery light coming on. A garage initially diagnosed alternator failure when it was just a £30 pulley!

Geoff
 
Thanks guys.
A loose belt might be a fair shout as well. I had a new alternator fitted and the timing belt and water pump all replaced about the same time. It’s been since the timing belt/water pump so presumably it was all stripped down then.
I’ve decided never to go back to my local Garage but I’ve got a recommendation from a friend - shame it’s MILES away (Clydebank).
I’ll maybe try Mr Birchill’s wooden stethoscope first.


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