Water Slushing sound on startup

[Gangly]

If I drive my truck for a good bit then let it sit for an hour or so, I will sometimes hear a water flowing sound from what I believe is the heater core immediately upon restarting it after sitting.  Like its sucking water up or something.  It last for about 1 second, immediately on startup, then I never hear it again, regardless of how long I drive.  It only occurs on startup, and is random at that.  Is anybody else familiar with that sound?  It has done it since day one and it never bothered me since I thought it was normal, but I just want to see if I am along in this or not.  I just hit 36k miles too...hope its nothing.

[OnTheReel]

Mine has done the same since day one.

[Gangly]

Funny how just reading your comment makes me feel better, at least I know I'm not alone

[Skirtbag209]

I had a 96 Silverado that would make randomly make the same sloshing noise. After owning it for some time I eventually had to replace the heater core. I can't recall if I started hearing the noise before or after it leaked/replaced. 

 

Currently, my 02 escalade started sloshing for the 1st time (in the 3 years of owning) a few days ago. 

[mrtizzom]

Mine does it also. Come to think of it, the last couple trucks I've had did this. I'm so used to it now that it doesn't bother me anymore lol