1990 Mustang LX 5.0 Water Sounds???

Sound strange I know, but when I start the engine I hear a sound like that of water gurgling coming from under the right side of the dashboard. Has anyone else experienced this? Any ideas of what it might be? I thought perhaps the sound is coming from the heater coil, but I'm not sure. Is this something to be concerned about? How can I correct it?

Thanks.

How is your coolant level? Ever smell antifreeze coming thrue your vents? Passenger floor board ever get wet, or the passenger side of the windsheild ever steam up? My first guess would be your heater core as well. But I cant imagine how it would make a "gurgling/boiling" sound. Car running hot when this happens?

Nice Mustang. I hope to refurbish mine some day when I can get another vehicle for everyday use. I have noticed the temperature gauge reading a bit higher than usual; I replaced it about three months ago when the gauge started reading very high, that seemed to help but it still reads high every now and then. I've not had any wet floor boards or steamed up windshield, nor do I smell antifreeze. I noticed this morning that even after running for 20 minutes the gurgling sound was there and more pronounced with higher engine RPMs. I'll check the coolant level tonight.

Thanks.

Does it do this at idle? It could be spark knock. You will best hear detonation when under a load.

It doesn't seem to be noticeable when idling, but only when revved a bit. It definitely sounds like liquid though.

When I am not pondering what the heck my grand cherokee is doing I am under the hood of my wife's '93 mustang 5.0. From time to time I have had minor coolant leaks between bad gasket matings and hose leaks, as well as a leaking radiator, numerous water pumps, etc... To get to the point, whenever I am low on coolant (it's amazing how low it can be and still run in the norm) I hear the gurgle sound you speak of. It is litterally water and air bubbling through your heater core, which you can hear because it's on your side of the firewall. When there is no air, there are no bubbles to make the gurgle. I look at it as a second way of knowing to add coolant. The first would be the low coolant light, but my GT never seems to siphon back from the overflow reservior like it's supposed to so it hardly ever goes dry enough to trigger the light. The gurgle cues me in though.

i had this same problem its the vacum hose for your a/c does your a/c work or need changed bottle could be lose you should check it out late mustanglx77