Technical Strange noise on start up

[Jimboc87]

Hi, my fiat punto 57 plate, is making a strange noise on start up. Goes away after driving for ten mins or so. Any one any ideas or pointers?

 

[Scoober82]

Looks like the alternator is new? How old is that belt? Does it only drive the alternator or is there air con or any freewheeling pulleys?

 

[Jimboc87]

Looks like the alternator is new? How old is that belt? Does it only drive the alternator or is there air con or any freewheeling pulleys?

Alternator is brand new, and belt is just for that as far as I’m aware. Air con doesn’t work -well doesn’t blow cold air only warm.

 

[bugsymike]

Alternator is brand new, and belt is just for that as far as I’m aware. Air con doesn’t work -well doesn’t blow cold air only warm.

Assuming alternator belt hasn't been over tightened, I would spray a little WD40 on the belt as a test, if noise changes or goes away temporarily, it's the belt.
If noise the same I suspect a duff new alternator.

 

[Scoober82]

They may have bypassed the AC pulley at some point if the belt is only running the alternator. So as Mike says I would spray the pulleys one at time and see if it makes any difference in noise. The belt looks as if it’s running straight with no wobble but are you sure the belt is new?you would clearly see the manufacturers stamp printed on it… if there are any gaps or splits in the belt or it has been over tightened it can cause an intermittent noise like that

 

[Jimboc87]

Sprayed some WD40 and no noise now so seems to have done the trick thanks for the help

 

[bugsymike]

Sprayed some WD40 and no noise now so seems to have done the trick thanks for the help

Remember that is not a cure, it merely identifies where the noise is coming from, so it sounds like a new belt correctly adjusted may be the answer.