check coolant sensor float most common problem.
it is low or out off coolant.
under the throtle body follow the big coolant hose that comes out from the upper part of the radiator tho the engine ull see a sensor screw in to the thermostat housing with two wires to it
possibly the water pump
should be located right above the #2 spark plug wire on the pipe that comes out of the block.
Fill your coolant to the level that it should be at. If it still comes on when the coolant is at its proper area, then it is an improper sensor. You will need to have it replaced immediately to reset the sensor.
Check your coolant first, if it's not low then replace coolant level sensor
Check your coolant sensor for built up sludge, or the sensor may need replacement.
The 1998 Chevy Malibu has two engine size choices. This car comes with either a 3.1 or a 2.4 liter.
Make sure the radiatpr is full and coolant overflow reservoir is at the full mark when cold. If it is full, Check the low coolant sensor located in the radiator on the passenger side. Had similar problem with my 2001 Impala LS I replaced the Coolant level sensor located on the radiator just behind the battery. Go to OE Warehouse.com use AC Delco #10096163 and get it cheap for $26.05 the exact OE sensor in your car now... Auto parts stores are asking $59.
bad coolant sensor
Check your fluid levels.
Turn it counterclockwise until it comes out.