See also:

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 ...

Using this Manual
To quickly locate information about the vehicle, use the Index in the back of the manual. It is an alphabetical list of what is in the manual and the page number where it can be found. ...

Footnotes — Maintenance Schedule Additional Required Services — Severe
a) Or every two years, whichever comes first. b) 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, wor ...