While you're under the hood bleeding the system, check for leaks. When was the last time you checked your coolant level?, or had a flush done? When the car develops a leak air gets in and creates air pockets causing those sounds you hear, as well as causing the temp gauge to raise if idling or at a stop light, even causing the car to overheat. Bleed the system and check for leaks.

 

Could be doors filled with water too, they might not be draining..

 

Holy $#@! i have the same problem, i just discovered it this week... my problem though is with BOTH the driver side door and the dash, towards the passanger side...At first i thought it was half empty water bottles, but then i realized that wasnt the case!. I noticed that after it rains in my neighborhood, the driver side door lets a woooshing sound when i break and come to a complete stop or accelerate (which is where the dash wooshing sound comes from).

my mechanic noticed that my coolant disappears quite fast and recommends a leak inspection... my car doesnt overheat though...

Any one else had the problem with water in the door also?

 

Look for a plug under the door, like the little plastic clips, I popped one out and water dripped out.

 

As others have mentioned, the sound you are hearing is coming from your cooling system. I've had the same sound right after doing cooling system flushes. Bleed the system, and you will be fine. And just as a precaution, check your coolant level and make sure its not low. If it is for some reason, take it in BEFORE your warranty expires, and make them do a cooling system pressure test.

Most likely its just air in the cooling system...

 

I just took the car over to the dealership and will post back what they say.

 

I appreciate all the advice. I took the car to the dealership yesterday and they said it was the water pump. It is being replaced and I should be getting it back today. They said the water pump was not providing the proper flow.

I was really surprised. My car never went above the halfway mark or fluctuated on the temperature gauge and I never saw any signs of leakage. I assumed that my cooling system was working properly. I only came about this problem by luck. I live in Texas and we just had our first cold spell of the year which of course lead me to use the heater. When I pulled up to the drive through of McDonald's, I started feeling cold air from the vents.

 

My water pump went in my Monte at 65K. My temp never budged either, nor did I see any leaks on the driveway. I smelt coolant when I opened the hood while the car was warm. Then after driving is home from Vegas one time, the next moring I noticed a small amount of steam coming out of the crack in the hood. So I opened the hood, smelt the coolant smell pretty strong, and saw very light steam on the passenger side of the engine bay. When I took it to the dealer, they pinned it on the water pump, and its been perfect since!

 

I had a coolant leak,took it in for a pressure test. They said it was the water pump. Said I should have the serpentine belt replaced since it had coolant all over it(made sense) Then they said these motors were prone to LIM gaskets failing, and might as well do plugs at the same time. Total $1550. I said thanks and left after paying $30 for the pressure test. Went to the auto parts store, bought a new water pump,serpentine belt and some coolant, replaced the water pump,serpentine belt and changed coolant. Total $120. Works great now. 3.4 water pumps are pretty easy to replace luckily. I wish it had been under warranty, I'd have someone else do the work in a heartbeat.

 

Pilotknob1964, thats great that you were able to replace it yourself, and everything is good to go! The mechanic is right in saying that the 3.4L is prone to LIM gasket leaks, so you should keep a close eye on your coolant level, and make sure its not going down, if it is, there is a chance you have a leaking LIM.

The 3.5L/3.9L's are not prone to this problem, thankfully GM finally fixed the leaking gasket probelms on their cars.