Low Coolant And wierd Noise from Passenger side?

[way2fast4u]

2000 chevy HOE 5.3

Ok lets see i noticed my Low Coolant light coming on everytime i was on sometype of hill or angle, so checked and refilled..

Now its on again and there seems to be a weird noise coming from the passenger side under glove box like (heater core) area, everytime i leave from a light i sounds like water or that type of noise moving around????? but no leaks!!! floor is dry, and coolant needs refill.. hopefully someone can help.. thanks..

 

[metro273]

That's the sound of air trapped in the heater core! Your cooling system needs to be bled correctly.