GM Service Manual Online
For 1990-2009 cars only
  1. Use a ¼ in drive in order to open and release the drain cock.

  2. Object Number: 339454  Size: SH
  3. If the drain cock does NOT seal when tightened, remove the drain cock, clean the drain, and replace.
  4. If the body of the drain cock is broken, remove and replace with a new drain cock.