i have a 1992 saturn sl2 1.9 liter DOHC with a squeaky serpentine belt at startup.

i don't think it's the belt because it only squeaks for about a mile or so, not for the whole time the engine is running.
it seems as though the squeak gets worse as more electrical accecories are turned on such as the A/C, blower, headlights etc.
i think a worn out belt would squeak for the whole time the engine is running.

how do i fix the squeak?

 

It's probably the belt. Shoot a little penetraiting oil on it when it's squealing. If the noise goes away you know it's the belt. And replace it.

 

Kinda depends on the squeak. You could have a squeaky tensioner. They will squeak for a bit and then stop once they warm up as will a belt. If the belt dressing doesnt quieten the squeak then try to direct a little of it into the tensioner and the other pulleys one at a time.
Hope this heps ya,
Billy

 

Saturn had a bulletin on a bad idler pulley some time ago---check Alldata.com. The dealer ate our repair under warranty from what I remember.

The fix is a new belt and revised idler pulley. See the Saturn parts counter guy for additional bulletin details.