Hi All
I have a VW Golf 1300 Mk2 81,000 miles.
I have just fitted a new Alternator drive belt, according to Haynes Manual I set the mid deflection to 2mm. After 500 miles I am supposed to check this and adjust to 5mm if required.
The belt does whine slightly, more so with higher engine revs, is this normal?
Does the belt slacken after 500 miles?
Andrew
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A belt that whines suggests that it is overtight. However a new belt will stretch ## after a few miles and will have to be retentioned, so maybe this is why Haynes suggest to set it to 2mm deflection when new, and check and adjust to 5mm after 500 miles. Personally I would give it a few miles, say 100, and if it still continues to whine, slacken it off slightly.
## Note: This refers to alternator belts, not cambelts. Cambelts have very little elasticity in them and once fitted generally don\'t need adjusting again.
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Are you sure it's not the cambelt whining?
Try a dab of grease on the running surface of the alternator belt, that might quieten it
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Try a dab of grease on the running surface of the alternator belt, that might quieten it
Or better still, use an aerosol rubber lubricant (can also be used on window rubbers)
Halfords stock this.
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Won't this make the belt slip?
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Won't this make the belt slip?
No!
The fluid is absorbed into the belt.
The product is designed for this purpose.
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I was really refering to the "dab of grease" but I'm a bit uncertain how the Halfords lubricant can be 'absorbed' into a rubber belt rather than coat the surface, do you know what it is?
It isn't the bearings whining and not the belt is it? In which case Dynamic Dave is likely right.
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P.S. I know natural rubber will absorb all sorts of things but aren't these belts pseudo rubber and non-absorbent? (Not trying to start an argument just interested).
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Keep the belt well clear of grease or any other "lubricants". If you are unsure whether this noise is the alternator belt or the cambelt, run the engine briefly with the alternator belt removed. The tension you describe seems very high, and is probably more than is necessary given the grip of these polyvee belts. I would suggest a deflection of 5 to 7mm under moderate thumb pressure at the centre of the longest run is about right. There is little point in needlessly hammering the alternator bearings. Recheck after 500 miles.
(ex Lucas CAV - Prince of darkness).
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I would check the alternater pulley for wear (even slight wear), a good condition second hand pulley cured mine. GGH
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In the old days, it was 1/2 inch deflection on the longest run of belt.
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.....but the dab of grease trick works in the real world and is fairly easy to administer; aiming an aerosol spray in the confined area of a belt run is sometimes very tricky!
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I seem to remember in the real world of very long ago brake fluid being used, whether Girling or Lockheed can't recall but whatever Morris Minors used! Presumably it made the belt tacky and prevented squeal.
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Brake fluid and rubber should go together without any problems...it is kind of oily so it would lube the belt whilst soaking into it to provide a durable coating at the same time.
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Thanks all.
I have readjusted the tension and noise has gone.
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