this problem has been there for quite long time, even though reporting it now. It was very strange and surprising to hear it first time. it felt as if water is splashing inside a large tank. it was more evident last summer and now hardly get noticed or there. but I do not remember getting it fixed anyway.

Rated this as fairly significant because it seems as if this is now related to my heat not working when my car is idle. Living in the northwest without heat in your car is not so great. Will find out soon once I take my car in to the mechanic to see what the problem is.

I have a 2005 Nissan Altima, well they still have not fixed the water sound problem that was reported in the 2003 model year. So frustrating!! I am taking the car to the dealer next week and have them bleed the cooling system and I dare they try to tell me more is wrong with the car, I am bookmarking this site and telling them to look at it before they give me some cocky story that I need a $1,500 repair for the heater core. I will post an update soon.