Troll Hunter Posted November 2, 2012 Share Posted November 2, 2012 My 300Tdi has developed a "squeak-squeak" from the fanbelt. It's two separate squeaks, close together, on each revolution of the belt. I've run it for about 2,000 miles with this noise, and it doesn't seem to be getting any worse, and I can't find any definite cause. Today I sprayed the fanbelt with belt dressing, and it became totally silent - for about 1 minute, and then it sounded like a can of loose bolts being shaken vigorously. Over the next 5 - 10 minutes the noise gradually subsided until there were just the two squeaks again. Intrigued, I repeated the spraying and exactly the same happened. Can the major noise be a failing/failed bearing, either in the water pump, alternator or tension idler? And if so, why does a spray of belt dressing result in totally silent running for a short while, since the belt dressing does not get into any of the bearings. If the major noise is not a bearing on its way to the great dump, what is it? And after the effect of the belt dressing has worn off, what's making the squeak-squeak? Any informed guesses, or better still, fact based explanations will be very welcome. Many thanks in advance. Mike Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted November 2, 2012 Share Posted November 2, 2012 Chances are there is something slightly amiss with the actual belt itself, fit a new one and it'll probably be quiet again :-) Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 2, 2012 Share Posted November 2, 2012 Funny this, as I had exactly the same problem when i fitted a brand new fan belt.. it squeeked so much I put the old one back on... I found that the PAS pulley look a bit squiff, took the pulley off to re-align but it still rotates like its not quite aligned properly... its quite apart from the odd chirup so I'm just keeping an eye on it. Take the belt off, spin all the pulleys feel them for play/tightness and see if there's anythign amiss... Quote Link to comment Share on other sites More sharing options...
dave88sw Posted November 2, 2012 Share Posted November 2, 2012 the squeek is usually caused by the belt tensioner, the nylon bush in it wears and allows the pulley to sit out of line. Cant think why the noise changes with belt dressing but with the belt off, try to rock the pulleys one by one to feel for play and spin to feel for roughness, replace anything that needs it. Quote Link to comment Share on other sites More sharing options...
Ratty43 Posted November 2, 2012 Share Posted November 2, 2012 I had this as well, the squeaking started as soon as I replaced a broken belt. I started with the 1p trick behind the tensioner which worked for a while. When the noise returned I replaced the tensioner bearing which also worked (combined with the 1p) for a whole as well. When the noise came back I ended up cleaning the belt and pulleys with a wire brush and that seems to have cured it. My theory is that rubber dust builds up and this causes the squeaking. Quote Link to comment Share on other sites More sharing options...
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