10W-30 should be the best type to use.
R134a
10w30
It should be perfectly happy with 10W30. Many oil change places are now using 5W30 as their default. My '96 ran just fine with that too.
A 1997 Pontiac Sunfire has an AC Filter located in the cabin. The filter can be found behind the glove compartment and is used replaceable.
5w30 weight.
Dexron 3 Wrong. Dex 3 is transmission fluid. Propolyene Glycol is antifreeze. Any good universal A/F is fine for this car.
Two sizes were used, P195/65-R15 & P195/70-R14
Dexron VI ATF or Dexron/Mercon Domestic Multi-Vehicle ATF.
Dexcool.
134a
i just did a engine swap in mine, i used one from a 98 sunfire gt, still the 2.4l. so any 2.4l motor from another sunfire should work, just make sure its from 1997 and up, or if you want to go to the extreme, a chevy cobalt ss motor also fits in as well,
You might take a look on Ebay Motors. There are usually some darned nice Sunfires (and other cars) listed for sale. FriPilot