2002 Chevy Impala low coolant light is on

make sure coolant level is where is suppose to be. take of radiator cap let engine run. might be air bound. if still doing it might have waterpump problems. but it sounds like air in system.

I had this same problem with my 2002 3.4L engine impala. Unfortunately, there was a coolant leak at the lower-intake manifold, caused by a cracked gasket. I replaced the gasket, water pump, thermostat, spark plugs and wires and flushed out the heater coil. Didn't find out what it was until after spending 100s on Dex-Cool. I kept refilling it for months until I got a good mechanic to fix the problem whom told me that this is a common repair on older impalas and GM vehicles with 3.4 and 3.1 engines.

This is usually the lower intake manifold gasket. The problem you are describing is due to a large air gap/bubble in your cooling line. This usually happens when the manifold gasket begins to fail.

You can add coolant, and bleed the coolant system (make sure to get out all the air to eliminate the no heat/overheat problem), but unless the lower intake manifold is fixed, it will probably contunue to leak (it can be a very very hard to detect leak). There are UV dyes u can add to the aNTIFREEZE TO CHECK FOR LEAKS THAT AREN'T OBVIOUS. But the worst case for this is that coolant gets in to the oil, and can ruin your engine. Check your dipstick for milky, creamy oil, a sign that there is coolant in the oil. Get it fixed immediately if this is the case, or you will ruin the engine.

There's info online about doing it yourself, but it's a bit invlved if you are not a mechanic. Expect to pay from 800 to 1200 to get it fixed at dealer or mechanic.