2002 alero low coolant

Slow leak.Could be almost anywhere.look for whiteish green corosion at hose connections,on the intake on the radiator or bottom of water opump to start.

IF LOW COOLANT LIGHT CAME ON ENGINE SHUT OFF BECAUSE IT GOT TOO HOT AND OVER HEATED.WHEN YOU HAVE LOW COOLANT.YOU COULD HAVE LEAKING RADIATOR.YOU COULD HAVE LEAKING RADIATOR HOSES AND WATER PUMP. ADD MORE COOLANT IN CAR RADIATOR UNTIL YOU AT FULL COLD MARK ON THE OVER FLOW COOLANT TANK START THE CAR LET IDLE UNTIL ENGINE GET OPERATING TEMPERATURE.RAISE YOUR HOOD LOOK FOR LEAKS THE RADIATOR PRESSURE WILL PUSH COOLANT OUT WHERE LEAKS COULD BE.LOOK AROUND RADIATOR AND COOLANT HOSES.LOOK AT WATER PUMP.IF YOU SEE COOLANT LEAKING AT WATER PUMP REPLACE IT.

the problem is in most cases in the probe for low colant light try to clean it if that dont work replace it. good luck. Hans

When engine cold , find coolant reservoir , usualy of white or yellowish container with black top and cap.
It has marks on it FULL and LOW.
Fill it up to FULL level and you done.
If it does'n have any coolant in there , then fill it up and run the engine for few minuts with open reservoir cap. Keep filling it up if level goes down , once it's stop or start to going up, close the cap and drive it around the block ,cause they have self bleeding cooling system.

That is the low coolant level indicator. Check the coolant level in your radiator and or reservoir. Add a 50/50 mix of antifreeze and distilled water. If you want to get an owners manual go here and sign up. http://www.gm.com/gmownercenter/gm/?campaignId=&vin=

Does the arrow point down. I think you are describing the low coolant level light. Add some antifreeze.

I also recently bought a 2002. According to the owner's manual the blue light does not indicate a problem unless it stays on after the car warms up. If you have an automatic it will not shift into fourth gear until the coolant warms up at which time the light should go off. Have only had the car for a week and notice the blue light goes off after a mile or two of driving in temperatures in the teens to 30's. I don't know how much outside temp affects it.

COLLANT LEVEL SENSOR IN RESERVOIR DIRTY/SHORTED

most likely idle air control sensor or low engine coolant I know sounds funny but IAC uses coolant to regulate idle. Idle air control valve or throttle body positioning sensor.

You must always check the coolant hot, expansion will cause a big change in level, how low was it? top it off hot and then drive a few days and recheck the level, I don't think you have an issue here.