S2 timing belt change -strange noise...
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peanut
Active member
Hi welcome to the forum .
wow I can't believe you'd take a chance on such a vital part .! belt failure could cost you a new engine.
Well firstly we need a little more precise informtion in order to guess what it might be
what kind of a noise is it ? buzz, scream, squeal, hum, knock ????????
does the noise increase and decrease with the revs ?
Does it come from the front of the engine ? take a long screwdriver or stick and put it on your ear and try see if you can narrow down which part of the engine it is coming from by touching the end of the stick on various parts of the engine .
I suspect you have either over-tightened the alternator belt and the bearing is squealing or part of the cam belt housing is touching the belts and rubbing .It could even be the added stain of a new tight belt on the waterpump pulley had started to damage the pump bearing but it could be anything .
wow I can't believe you'd take a chance on such a vital part .! belt failure could cost you a new engine.
Well firstly we need a little more precise informtion in order to guess what it might be
what kind of a noise is it ? buzz, scream, squeal, hum, knock ????????
does the noise increase and decrease with the revs ?
Does it come from the front of the engine ? take a long screwdriver or stick and put it on your ear and try see if you can narrow down which part of the engine it is coming from by touching the end of the stick on various parts of the engine .
I suspect you have either over-tightened the alternator belt and the bearing is squealing or part of the cam belt housing is touching the belts and rubbing .It could even be the added stain of a new tight belt on the waterpump pulley had started to damage the pump bearing but it could be anything .
Guest
New member
Hi & thank you for the prompt reply. In response to "what sort of noise?" this is always difficult to answer as it's entirely subjective.
Put it this way, I fitted a complete cambelt kit including a new water pump (£ouch!) and when the 'noise' first developed, I suspected it was a water pump bearing on the new pump. Stripped, inspected (water pump was fine) and re-fitted, but the 'noise' remained.
With regards to tension, that's fine. Checked and re-checked (& checked again !)![[FONT=verdana,geneva"]](/forum/styles/default/pcgb/space.gif ". [FONT=verdana,geneva\"]")
I posted a similar question on the Piston Heads Gassing forum - please see th response below in italics.
Closer inspection of the belt does indeed show that although the dimensions are exactly the same, the teeth do appear slightly different - I will try an OEM belt & see what happens.
Thanks again. Julian It has been reported before that some aftermarket belts - particularly with a shapr at the tip of the teeth that makes it look like a double tooth - can create windage noises as the gap closes in on the sprocket.
I cannot verify this but if everything else checks out - it could be the reason for the noise.
Another possibility comes from a new belt being stiffer than an old belt and therefore although the linear tension may be set right the load put on old rollers from the stiffer belt being forced around in curves as it passes round the rollers - could make an old roller sound more noisy - if so the noise should recede with time or a new roller is needed.
If a new cam belt is changed the same applies to the water pump as this also forms a roller and sometimes this explains why a new belt can quickly kill of an old water pump.
Baz
Put it this way, I fitted a complete cambelt kit including a new water pump (£ouch!) and when the 'noise' first developed, I suspected it was a water pump bearing on the new pump. Stripped, inspected (water pump was fine) and re-fitted, but the 'noise' remained.
With regards to tension, that's fine. Checked and re-checked (& checked again !)
I posted a similar question on the Piston Heads Gassing forum - please see th response below in italics. Closer inspection of the belt does indeed show that although the dimensions are exactly the same, the teeth do appear slightly different - I will try an OEM belt & see what happens.
Thanks again.
Julian It has been reported before that some aftermarket belts - particularly with a shapr at the tip of the teeth that makes it look like a double tooth - can create windage noises as the gap closes in on the sprocket. I cannot verify this but if everything else checks out - it could be the reason for the noise.
Another possibility comes from a new belt being stiffer than an old belt and therefore although the linear tension may be set right the load put on old rollers from the stiffer belt being forced around in curves as it passes round the rollers - could make an old roller sound more noisy - if so the noise should recede with time or a new roller is needed.
If a new cam belt is changed the same applies to the water pump as this also forms a roller and sometimes this explains why a new belt can quickly kill of an old water pump.
Baz
peanut
Active member
it should be possible to determine if the sound increases and decreases linearly with the revs.
This is an important diagnostic because right away it eliminates a whole stack of other possible causes at a stroke.
I would still recommend that you use a bamboo cane or some sort of wooden rod or dowel to listen the the engine. Its the best diagnostic tool you got in your box. Systematically place the rod on every part of the engine and anxillary gear and place the other end to your maxilla just in front of the ear and listen. It will not take you more than 5 minutes to pinpoint exactly where the sound is coming from . You need to be our eyes and ears if we are to help you otherwise we are guessing blind
This is an important diagnostic because right away it eliminates a whole stack of other possible causes at a stroke.
I would still recommend that you use a bamboo cane or some sort of wooden rod or dowel to listen the the engine. Its the best diagnostic tool you got in your box. Systematically place the rod on every part of the engine and anxillary gear and place the other end to your maxilla just in front of the ear and listen. It will not take you more than 5 minutes to pinpoint exactly where the sound is coming from . You need to be our eyes and ears if we are to help you otherwise we are guessing blind
peanut
Active member
the other simple thing you could do is to remove both the steering pump and alternator belts . if the noise goes away you have found your cause. If it doesn't you have probably narrowed your search to belts pulleys tensioners and bearings related to the cam and balance shaft belts
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