See Engine Compartment Overview for the location of the engine air cleaner/filter.
When to Inspect the Engine Air Cleaner/Filter
Inspect the air cleaner/filter at the Maintenance II intervals and replace it at the first oil change after each 50,000 mile (80 000 km) interval. See Scheduled Maintenance for more information. If you are driving in dusty/dirty conditions, inspect the filter at each engine oil change.
How to Inspect the Engine Air Cleaner/Filter
WARNING:
Operating the engine with the air cleaner/filter off
can cause you or others to be burned. The air
cleaner not only cleans the air; it helps to stop
flames if the engine backfires. Use caution when
working on the engine and do not drive with the
air cleaner/filter off.
Notice: If the air cleaner/filter is off, dirt can easily get into the engine, which could damage it. Always have the air cleaner/filter in place when you are driving.
To inspect the air cleaner/filter remove the filter from the vehicle and lightly shake the filter to release loose dust and dirt. If the filter remains caked with dirt, a new filter is required. Never use compressed air to clean the filter.
To inspect or replace the filter, remove the screws that hold the cover on and lift off the cover. Be sure to reinstall the cover tightly.
Chevrolet Cobalt Owners Manual. Engine Coolant Temperature Warning Light
This light comes on briefly
while starting the vehicle.
If it does not, have the vehicle serviced by the
dealer/retailer. If the system is working normally
the indicator light goes off.
Notice: Driving with the engine coolant temperature
warning light on could cause the vehicle to
overheat. ...