Z71-liquid sound in dash

[97z71 & 97 yukon]

I have a strange liquid sound like "sloshing" water inside of the dash on my 97 z71. I have already checked the heater core and have no leaks. I have already made sure that the A/C duct drain is clear.It seems to be worse during the summer ,so I suspect condensation is getting trapped in the A/c ducts somewhere Any ideas?

[TexasF355F1]

I remember having this sound in my truck every so often. Never knew what it was or worried about it.

[wrparks]

My dad's 97 did pretty much the same thing. We always assumed it was the heater core opening up to let in more hot coolant, but never cared enough to look. As far as I know, it still does it years later, and he still drives it.

[waitingforcolumbus]

My '99 made a sloshing sound from the heater core. The engine coolant was low and air was trapped inside there. I refilled it while hot with the heater on and the noise has not returned.

[Elbert]

most likely an air pocket in the cooling system. Make sure truck is full of coolant and has some in the overflow tank too. The way to get rid of an air pocket is to open the radiator cap with the engine cold, turn on the heat and high fan and let truck run until the thermostat opens......verffify coolant level and replace the radiator cap.

[DocHoliday1RGW]

Agree... just went through that with my impala.... I made an easy fix hard. At the very least do the fluid level thing before you waste alot of money other wise.