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I'll give that a try, and check to see how tight the belt is, thanks for the tip!
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Try squirting the bearing behind the alternator pulley - it can squeal (or worse) when 'dry'. Maybe the belt is a bit tight?
Ok, just gave the alternator pulley a good dose of WD40, then started the car and the noise has almost gone, a definite improvement. I also checked the tightness of the alternator belt and to me it does feel a bit too tight. If I remember correctly, the belt should be able to be turned 90 degrees at it's longest point between pulleys when fitted, however I can hardly turn my belt 45 degrees. Does that sound too tight?
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Depending on the length of the longest belt run, you should be able to twist 90 degrees. If the noise has stopped after you have soaked the alternator pulley, it’s a fair chance that the bearing is now damaged.
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Depending on the length of the longest belt run, you should be able to twist 90 degrees. If the noise has stopped after you have soaked the alternator pulley, it’s a fair chance that the bearing is now damaged.
Well I definitely can't twist the belt 90 degrees so in my opinion it is way too tight. Can the pulley be changed on an alternator, or does a whole new unit have to be fitted?
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Check the crankshaft pulley. These have an anti vibration damper incorporated into its construction that can separate and cause slipping.
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Check the crankshaft pulley. These have an anti vibration damper incorporated into its construction that can separate and cause slipping.
Will do, how's best to check the crankshaft pulley and what do I need to be looking out for?
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Remove the polyvee belt and check if there is any movement between grooved part of the pulley and the centre hub where the bolt is located. Something else that may show , is a rust line between the metal part and the rubbberised part of the pulley. Also check the belt for wear . If the grooves are badly worn, the belt will lose grip. Turning the belt through 90 degrees does not apply here as it has an automatic tensioner.
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Hi All
Well after an investigation into the whistling / squealing noise I think I may have discovered the issue, although not completely certain.
I removed the drive belt, it looked fine to me but I will replace it any way for the small cost involved. Had a look at the crankshaft pulley, couldn't see anything out of place and there was no movement to be found. Checked the air con pulley, that spun smoothly and quietly, as did the alternator pulley. However, the drive belt tensioner pulley felt quite rough when spun around and sounded quite loud, like there was some sort of grinding going on inside, although it did spin quite freely. I'm not 100% sure what the tensioner pulley is supposed to sound like but I'm assuming it should have spun as quietly and smoothly as the air con and alternator pulleys, would that assumption be correct? Can you just replace the pulley on these automatic tensioners or does the whole unit need to be replaced? The tensioner works as it should, it's just the pulley that doesn't seem right to me.
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You are probably right to suspect the tensioner. My Pug 205 started squealing like this last year, and it could be alleviated somewhat by lubricating the alternator bearing. After a while the engine refused to run, but luckily the timing belt had not slipped enough to cause serious damage. Cambelt kit replacement (includes new tensioner) cured the problem. So I would recommend you get that done soonest in case worse happens.
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You are probably right to suspect the tensioner. My Pug 205 started squealing like this last year, and it could be alleviated somewhat by lubricating the alternator bearing. After a while the engine refused to run, but luckily the timing belt had not slipped enough to cause serious damage. Cambelt kit replacement (includes new tensioner) cured the problem. So I would recommend you get that done soonest in case worse happens.
My squealing is from the auxiliary drive belt tensioner, not the cambelt one, so it won't be that drastic if the drive belt fails. Had a new cambelt kit fitted on my C4 about a month ago.
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<< My squealing is from the auxiliary drive belt tensioner, not the cambelt one, so it won't be that drastic if the drive belt fails. Had a new cambelt kit fitted on my C4 about a month ago. >>
Yes, apologies. You can live with the squealing if you like, it's not a toothed belt and wouldn't cause too much harm ....
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Belts are so good now that I think their tension pulleys are most likely to fail first. About eighteen years ago I easily replaced a squealing stiff cambelt tension pulley on our 1994 Passat 2.0GL at around 140,000 miles. The original cambelt looked fine so I left it alone, especially as it was too difficult for me to change. It was still OK at 242,000 miles when we sold it. I'm keeping a close ear on our Focus...which is approaching 140,000 miles, albeit far more slowly than in those hectic school run days.
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