Sloshing noise

During the past winter, my car started to make a sloshing noise coming from what appears to be behind the radio, heater controls. I noticed that the noise was most evident when the weather was sunny and warm. Mechanics could not find the problem and it actually disappeared when the temps dropped below freezing. This Spring and summer, with the warm weather, the noise has intensified and sounds like a pronounced sloshing noise, as if a liquid were being moved around. The mechanics are still at a loss as to what is creating the sound. There is no liquid leak and all liquid levels are full. Help. I am tired of driving around wondering if I am going to get splashed with a gallon of water. The car does have 186,000 miles, but still drives like a dream.

The last time I worked on a “sloshing” noise it turned out to be air in the engine cooling system. I removed the trapped air and the noise went away. I have also heard of a plugged AC drain causing this but you usually have water in the front floorboards after using the AC for awhile. Hope this helps.

Thanks, both have been checked and still have the noise.