When inspecting cylinder compression, the engine should be at room temperature, the throttle should be open, the spark plugs removed and the battery at full charge. The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 100 psi. Turn ignition key until engine cranks through four compression cycles per cylinder. Normal compression builds up quickly and evenly to specified compression on each cylinder. |
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.
...