How to determine and eliminate what is squeaking in the drive belt area ?

[Rightboy91]

Car is a 57 plate Vauxhall vectra 1.9 cdti 120 bhp.

I replaced the drive belt and tensioner about 3 or 4 months ago and everything was totally fine with it .
About 5 weeks ago I heard a squeak when I start up the engine it woud olny last about 1 second as the car was started, but also it can be heard when the car is in reverse and most audible in gears 1 and 2.
it isn't as terrible as some drive belts make when they go bad but it is still quite loud , it is more of a squeak than a squeal thoguh it does squeal faintly sometimes.

How can I determine which pulley is causing this ? I feel sure it won't be the the tensioner as its basically new.
I had the belt off and tried the pulleys they spin freely and doesnt seem to be any wobble on them.

thanks

 

[Mottie]

Here we go, another 10 pager!

 

[Rightboy91]

on

Here we go, another 10 pager!

only if the trolls return and litter the thread with trash

 

[Burnerman]

Belts only squeal if they are a bit slack....when the car starts up, there is a high drain on the alternator, and the power steering can also play up unless it's electric.
The squeal is usually due to the belt slipping rather than the tensioners.
John

 

[Harry Bloomfield]

Sprinkle talc around the area of the belt.

 

[freddiemercurystwin]

Sprinkle talc around the area of the belt.

There's a joke in there somewhere.

 

[Harry Bloomfield]

There's a joke in there somewhere.

Sorry, not a joke, a genuine fix.

 

[Bodgedbuild]

If the belt is thrashing around it is probably the alternator clutch pulley, sometimes called a sprag pulley. This pulley has a one way clutch so with the belt off it should be locked in one direction and spin the alternator armature but it should provide very little drive to the armature in the other direction.

 

[dontbelieveawordofit]

cheap belt

 

[Harry Bloomfield]

If the belt is thrashing around it is probably the alternator clutch pulley, sometimes called a sprag pulley. This pulley has a one way clutch so with the belt off it should be locked in one direction and spin the alternator armature but it should provide very little drive to the armature in the other direction.

Not doubting you, but why would an alternator have or need a clutch, the engine only rotates one way, the alternator can only be driven one way?

 

[Keithmac]

AC pulleys have an electo-magnetic clutch but I've not come across an alternator with any type of setup other than a fixed pulley.

 

[Stivino]

I believe some Vectras do indeed have an alternator clutch pulley.

 

[Keithmac]

Every day is a learning day!, begs the question why they decided it was necessary.

Seems like just something to go wrong with no real benefit?.

 

[Mottie]

Not doubting you, but why would an alternator have or need a clutch, the engine only rotates one way, the alternator can only be driven one way?

Plenty of engines with four, five or more pulleys and a serpentine belt have alternators with a clutch pulley on them nowdays. Our Golf has one, our Evoque has one and the last three alternators I’ve changed have had one. They don’t half make a rattle and make the belt bounce when they seize up! This explains it: https://idpartsblog.com/2018/07/09/clutched-alternator-pulleys-are-important/

 

[Harry Bloomfield]

Plenty of engines with four, five or more pulleys and a serpentine belt have alternators with a clutch pulley on them nowdays. Our Golf has one, our Evoque has one and the last three alternators I’ve changed have had one. They don’t half make a rattle and make the belt bounce when they seize up! This explains it: https://idpartsblog.com/2018/07/09/clutched-alternator-pulleys-are-important/

News to me, but still seems a strange way to do it with a mechanical clutch. It would be less complicated and cheaper to simply switch the electrical load off, to achieve the same effect of a freewheeling armature. My car has four pulleys driven by one belt, then a second smaller belt driving the a/c compressor. All I hear is a slight click as the a/c engages, but only with my head under the bonnet and a change in the engine note.