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Discussion Starter · #1 ·
have a 2005 1.5 dci megane, there is a high pitched noise coming from the alternator that gets louder as revs increase, put the screw driver to my ear then the alternator, i think it might be the alternator clutch. can these be bought, easy enough job? or best changing alternator
 

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Technical Supremo, Platinum, I let the Dogs out
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silly question, are you certain it has a clutch on it or is it just a pulley?
 

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Captur 2017 1.5DCi EDC
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alternator bearings - plenty of help on youtube.
 

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have a 2005 1.5 dci megane, there is a high pitched noise coming from the alternator that gets louder as revs increase, put the screw driver to my ear then the alternator, i think it might be the alternator clutch. can these be bought, easy enough job? or best changing alternator
By the clutch pulley puller off eBay, £12, and find pulley same part no, off said site! Save your self £100+ don't leave it too long at they seize and snap the belt.

Sent from my SM-A320FL using Tapatalk
 

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Super fantastic Mod Technical Supremo Nice Guy
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DO not forget to use some thread locking compound,
 
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Premium Member
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Discussion Starter · #7 ·
ill get a video up to be sure, am guessing the barings inside the alternator fail aswell? i just put it down to the pully
 

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Technical Supremo.
Scenic II, 2004, K4MW761, DPO
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If you keep the revs constant at say 1500 , and with the headlights switched on ................


Is the noise worse at this stage than when you let the revs drop sharply?


Reason I'm asking ........... the sprag clutch inside the alt bearing/pulley assembly, locks up when the engine turns faster than the alternator armature (read fixed heavy electrical load with constant engine speed with the engine driving the alt hard) and thus cannot/should not make any noise under those conditions. If however you have just about no electrical load going and are able to make the alt spin faster than the engine (during rapid deceleration) and the clutch or ITS own assembly bearing is to blame, then you will have extar noise only under those conditions.


If you are however able to say that there is a simple and direct link between engine speed and the noise you hear with the screwdriver as stethoscope experiment, then I am afraid I would suggest look at the actual front and rear bearings on the alternator itself first.
 

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Technical Supremo, Platinum, I let the Dogs out
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This is the noise my alternator made when the bearings went


 

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Grand Scenic 1.6 2007
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High pitch is relative but generally a shriek is a loose belt and it's worse as you accelerate and tends to go away at constant speed.
One way pulleys tend to lock up rather than cause noise. The belt should run smooth at idle. If the tensioner pulley can be seen moving without having to peer at it the clutch is locked. Ask an assistant to stop the motor and the innards of the alternator should run on for a good second or so without causing belt jump.
Next take off the belt and turn the pulley gently. You will feel it if the bearings are rough.
While you're there you can check for clutch action by flick twisting the pulley in both directions. One should be locked, the other break free with sharp flick. This is not a definitive test that the clutch is ok. They can go into a twilight zone of making crickety clicks with the tensioner steady and then quiet with the tensioner flapping about.
 

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I have a Mk2 Alternator in stock, Fitted with brand new quality bearings.
Pulley Looks OK, Passes all the previously posted checks. Even been stripped & Checked. (Had to to change bearings)
Makes hell of a racket on the car, But spun up on a battery drill is silent.
Got so Pi55ed off with it, Went to a scrappy in -2C & bought another. Which was cheaper than the stoopid clutch pulley. :crying2:
 

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Super Moderator Technical Supremo Platinum Member
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.........Which was cheaper than the stoopid clutch pulley. :crying2:
Wasn't going to mention as Meg pulleys seem cheaper then the beasty my Kia needed when it collapsed.
Best I could find was 90 quid and then the hassle of replacing.
But I found a local repair place who collected old alternator, checked it, replaced all bearings and pulley then delivered back to me for the same price... six years later, still running so no complaints on quality of work.
Biggest issue for me was getting the bu55er out.... if someone had told me it was a 4 hour job before I would have laffed at them. But it is a right pain tucked down the back of the engine.
 

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Super fantastic Mod Technical Supremo Nice Guy
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Just lift the engine off its mount and force a piece of wood down the back
 

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Super fantastic Mod Technical Supremo Nice Guy
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I hit reply Pete, then Advanced, and low and behold, the bloody thing was up on here,,
As was going to put,, then send for a mechanic.....

I had more problems putting the belt back on than getting the Alternator off or on.
 

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Technical Supremo, Platinum, I let the Dogs out
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sounds pretty much like mine but my wife was a bit more gentler on the throttle :) - mine was bearings allegedly, thats what the garage said when they replaced the alternator under extended warranty
 

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Grand Scenic 1.6 2007
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Just lift the engine off its mount and force a piece of wood down the back

You might want to rephrase that ?


Anyway, sounds like bearings of some description. There's more than an alternator on that belt. Don't put the blinkers on :)
 
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