Footnotes — Maintenance Schedule Additional Required Services — Normal
a) Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. Check that the purge valve, if the vehicle has one, works properly. Replace as needed.
b) Or every four years, whichever comes first.
c) Or every five years, whichever comes first. See Cooling System .
d) Or every 10 years, whichever comes first. Inspect for fraying, excessive cracking, or damage; replace, if needed.

See also:
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap ...
Other Warning Devices
If you carry reflective triangles, you can set them up
at the side of the road about 300 feet (100 m)
behind your vehicle. ...
Engine Oil Additives / Engine Oil
Flushes
Do not add anything to the oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all that is needed for good performance
and engine protection.
Engine oil system ...
