Originally Posted by Trav
The Dayco for this engine is probably OE, for these engines it would be the one I choose because in my experience if they were the OE manufacturer and the engine is low production as this is they just box the OE part not start an aftermarket quality line. Gates buys and boxes cheap Chinese parts, Replacement brand is just crap.
$20 cheaper than Rock when you count the shipping cost from Rock.
Dayco 89240
That Dayco 89240 does not appear to be the right part for his vehicle, and the info I'm seeing contradicts that Dayco is the OE. The pictures on O'Reilly's makes the Gates look like the ACDelco part # while the Dayco does not look the same. I know pics aren't always reliable (even two of the gates look different!) but in this case what is shown for the Dayco looks like the lower quality aftermarket part. The Dayco looks like the cheapest ultra-power on Rock Auto and the no-name brand on carparts.com (see link below).
I would get the Gates, but on Rock Auto because they have them on closeout for $24, or the ACDelco on Rock Auto for $57.
Rock Auto Belt Tensioners
However the ACDelco or regular price Gates ($42) have lifetime warranties while the closeout $24 option is only 30 day warranty, BUT I wonder how long a lifetime it needs to be for a 23 y/o vehicle. If it's in great shape and you plan on keeping it long term then I'd get the ACDelco. The regular price Gates is also cheaper (at $43, because of free shipping) from Amazon.
Amazon Gates 38112
Also considering the age of the vehicle, "IF" the tensioner is still working good (not at the end of its travel range and the belt is not flopping wildly with engine running) then you can replace just the pulley cheaper, around $15. I would replace the whole assembly on a newer vehicle but I don't know the condition of the '97 Saturn.
ALSO consider that the noise may not be the tensioner at all. It is likely but could be anything belt driven (or not belt driven, take the belt off and start the engine to check this), including the idler pulley among other things. Have you had a helper try to locate the noise location while you start the engine? Granted a short high pitched noise can be very hard to locate by hearing.