Before leaving the vehicle, fully press the clutch pedal down, move the shift lever into R (Reverse), and firmly apply the parking brake. Once the shift lever has been placed in R (Reverse) with the clutch pedal pressed down, the ignition key can be turned to LOCK/OFF, then remove the key and release the clutch pedal.
See Manual Transmission Operation.
Chevrolet Cobalt Service & Repair Manual. Engine, Replace
Removal
1.
Open and support hood. Install suitable
protective covering over fenders. Mark upper hood hinge location
to hood with suitable grease pencil. Remove hood with assistance.
2.
Remove air cleaner resonator to accelerator
...