The tachometer displays the engine speed in revolutions per minute (rpm).
Notice: If the engine is operated with the tachometer in the shaded warning area, the vehicle could be damaged, and the damages would not be covered by the vehicle warranty.
Do not operate the engine with the tachometer in the shaded warning area.
Chevrolet Cobalt Service & Repair Manual. Motor Vehicle, Inspection
A visual inspection must always
be performed to confirm the presence of aftermarket components, potential
collision damage, or areas of concern.
1.
Inspect service history of vehicle.
2.
Inspect engine oil level.
...