It takes 5w30. Use synthetic blend.
you have to take the timing chain off
Dexron III, but check with any auto store first.
R134a
You take it out and put a new one in
No!
10w30 says it right on the oil cap.
Gool ol' Dexron.
Try Amazon.com and see if they have some Buick manuals from Chilton or Haynes. I know they have diagrams and instructions.
Any major brand 10w30 high detergent oil.
I got a '94 Buick Skylark Custom Sedan, but all are the same, first pull your back seat down, just grab it and jerk it and it will fold down where you can work. Then take a knife and pop the black plastic bolts holding the cover on in the back window, this covers the whole back. Then just unscrew the screws holding the speaker in, and then lift out. That's it.
Take it to a body shop.
This is not an easy job. You have to take the a/c ducts out from under the dash etc. Get a manual at the parts store or DISCOUNTAUTOREPAIRMANUALS.COM