This is an odd question, but just something i was wondering. If the accessory belts (alternator or A/C) are loose or have stretched (after a new install) on the engine they squeal, but only when the car starts up. Why is it only then, and not the entire time you're driving the car?

 

I don't know, but it could be that they're cold and less flexible, or the speedy change in engine speed (from 0 to ~500 rpms) could cause them to slip a little, or maybe you just can't hear them the rest of the time due to road noise/ engine noise. It would seem like they'd slip most if you have the clutch in and are doing something since otherwise your accelerating your whole car so the revs aren't changing real fast. Hope that made sense and GL

 

You need to adjust the belt tensioner. I had the same problem after installing a UD pulley with new belts. They are either too loose or too tight.

 

Most likely too loose.

 

Hahahaha. I know why it sqeals i was just wondering why it only does it when yous tar tthe car.

 

When the engine is not running none of the pullies are spinning so when you turn the car on and the belts are loose youll hear it slip. The friction of metal / rubber makes the squealing sound.. so after the car is on even at idle the belts wont have a chance to slip but you should still get it adjusted.