See also:

When to Check and Change Lubricant
It is not necessary to regularly check front axle fluid unless there is a leak suspected or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired. ...

If No Steam Is Coming from the Engine Compartment
If an engine overheat warning is displayed but no steam can be seen or heard, the problem may not be too serious. Sometimes the engine can get a little too hot when the vehicle: - Climbs a long h ...

Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if ...