Coolant leaks heavily from passengers side. Started yesterday morning on the way to work. I noticed the vents weren't blowing hot air. Then I noticed the car start to overheat. I didn't drive any more than two miles. When I pulled over I noticed the dripping under the car. There was no smell in the car and the hoses going into the firewall seem fine. I replaced the water pump in May 2013 when it seized. Could it be the water pump again? Anther suggestion I was given was the thermostat. I have started the car (to get it on ramps) and noticed that there is a gurgling sound coming from the same area and coolant leaks terrible while just staying idle for a few minutes. Any help is greatly appreciated!! Thank you!!

SOURCE: Chevy S10 overheated, now heat doesn't work, leaking coolant

When an engine is overheating and then the temp drops on the guage, it's usually a sign that the coolant is not touching the temp sensor. There's no coolant in the engine. Putting water in the overflow tank won't solve this. Take the radiator cap off after the engine cools and put coolant in the radiator. you might have to crank the engine and do this several times, as the engine can develop air pockets that won't allow the coolant to travel inside the engine. If you don't see any leaks, and it still uses coolant, you've probably got a blown head gasket. Check for water on the plugs, check cylinder compression. If it slowly uses coolant, try putting a large box of pepper in the radiator or some of that radiator seal copper flakes.

SOURCE: 2002 Chevy Impala low coolant light is on

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.

SOURCE: My 03 Trailblazer was making a loud squealing

Have you tried to checking the tensioner and the idler pulley? The idler is a fixed pulley on the driver side of the alternator. Most of the time this gets rusted during sudden change in the weather or its just the bearing inside it just worned off.