Squealing drive belts
 

So when I start my car it always makes a squealing noise, coming from the drive belts. I recently replaced them, and I figured they might not have been tensioned good, so I adjusted that today. Well after I started the car up it squealed again. It goes away after like 1 second, but it's still annoying.

Should I just go buy some belt conditioner or whatever it's called? Is it normal to have to apply belt conditioner to new belts to prevent the dreaded squealing?

bump.

From what you are saying, the squeaking is probably coming from the PS pump, A/C compressor, alternator, or idler pulley. Try removing the PS belt and then the A/C belt to see whether the squeaking goes away. If not, the problem may be the alternator (bearing).

It makes the same squealing noise as a wet belt, as if I had driven over a puddle and had water splashed onto the belt.

I think that belt squeak might be difficult to distinguish from a metallic bearing squeak.

I think i will try some WD-40 on the idler pulley and see if the noise goes away. If the noise goes away, then I have isolated the problem. If it doesn't go away, then I still haven't completely proved that it wasn't the idler pulley because I can't assume that WD-40 should have necessarily silenced the bearing if it was in fact the problem.
This makes sense, right?

I would avoid the WD40 as you risk getting it on the belts, which isn't a good idea.

is there another lubricant i can spray on the idler pulley (using one of those aerosol cans/straw for accuracy and to lessen the risk of getting it on the belts) that you can recommend, or is any lubricant on the idler pulley a bad idea because of the previous reason with WD-40 that you stated?

Also, i'd like to mention that when I had the A/C on (what I am about to mention only occurred once) one time while pulling into a parking lot, as soon as i pressed in the clutch, therefore making the engine idle, it made the same squealing noise for a split second.

Even if you could accurately spray a lubricant on the idler pulley bearing area, I am not sure it will give you the answer you seek.

Whether the A/C is ON or OFF, the idler pulley is spinning. If you never hear the squeak with the A/C OFF, then you would consider the compressor.

I would try sequential removal of the PS belt and then the A/C belt to determine whether spinning of the PS pump versus compressor/idler pulley is linked to the noise.

I know it can't be the compressor, it's new (just installed it about a month ago).

I think before I go taking anything apart i'm going to triple check the belts' tension and make sure they are all correct and then see if it makes the noise.

If it turns out to be the idler pulley, isn't the idler pulley really inexpensive? I think if triple tensioning the belts doesn't solve my problem I may go ahead and replace the idler pulley (if it's like 20 bucks) since to replace that all i have to do is relieve the a/c belt tension and remove the pulley, and then see if it fixes it. If not, I will still get a new idler pulley out of it, and i remember that mk378 said that I should replace the idler pulley when replacing the a/c belt, which I did not do when I replaced the belt.

The only purpose the idler pulley serves is to be able to adjust the tension of the a/c belt, correct?

EDIT: I found that idler pulleys are only like 35 bucks, I may just go ahead and replace it. Do you think that this squealing noise is urgent to be fixed?