'99 Alero

Hello there. I have a friend who bought a used '99 Alero and it did not come with an owner's manual. Can anyone tell me what the factory recommendation is for the weight of oil she should use?

Thanks a bunch,
Christina

The filler cap on my 2000 3.4L says 5W-30

The filler cap on my 2000 3.4L says 5W-30

5W-30 is the recommended for most driving conditions and temperatures per the Alero owner's manual.