a bad head gasket or intake manifold gasket.
It could be that you need coolant or it's low.
A worn transmission gear can cause a Chevy Impala to whine when the gears change. A bad fan belt can also cause this.
If the fan is not blowing, a fuse may be the cause. If there is just not warm air being blown by the fan, check your coolant level in your radiator. Low level of water and coolant will cause the heater to blow cooler air.
water pump, oil, water, engine coolant....main cause would be engine coolant, just check to see if you have a leak.
ON the 2006 impala that whining noise is actually the electronics when you accelerate. Its more or less electronic pulses/signals My 06 Impala is the same.
Leak in heater core
well basically you need to fill your coolant system up I'm not familiar with Chevy's but refer to the car manual
No, cause if you do, the car will blow up due to lack of air circulation...
Thermostat.
Yes, internal coolant consumption can damage a catalytic converter.
Yes it sure can.
It could be a weak battery or a bad ignition coil.