Why is my car making a gurgling noise behind the steering wheel?

I found out what this was the hard way. It's a sound almost like water moving in a stream. My car never was showing hot, the overflow tank was at the proper level as well. However, there was an air bubble in the system. When your car is cool, open the radiator cap and make sure there is coolant up as high as it can get inside the radiator. If it isn't, fill it up and start your car. Watch for when the thermostat opens and it should suck in coolant. Keep adding coolant until radiator stays full when your thermostat opens. Replace radiator cap and make sure the overflow tank is at the full hot mark. If you notice any creaminess in your engine oil, you have had that air bubble for a while and blown the head gasket and possibly warped heads.