Bubbling Sound?

[zamboni]

I was in my dads 04 Avalanche the other day and there was a bubbling sound coming out from behind the dash. He is hard of hearing and can't really hear it himself. I first heard it when it was running, then when he shut it off, I turned the key to on, but didn't start it and you could hear it then as well. Is it the heater core?

[Macgyver55]

Has he been using the A/C lately? Sometimes its just the normal equalizing of the refrigerant when you shut it off. Or, what I've run into before on some other vehicles in some cases were the drains being plugged on the heater/evaporator box. This was allowing water to build up to the point where the blower motor was blowing the water making a gurgling sound. If the blower is on, try turning it off and see if the noise stops.

[zamboni]

The AC wasn't on, and the fan wasn't on. any other things it could be?

[Jeremy airjer W]

Low on coolant?

[zamboni]

I will check that tomorrow

[crothmeier]

i would guess the coolant. the overflow resevoir is up by the dash on the passenger side, under the hood isnt it?