I have owned this vehicle since new and recently it randomly makes a strange noise which seems to originate from under the cowling/firewall. I would describe is as is water steam escaping and at first thought it was water boiling in the battery. I removed the battery from the vehicle and the sound continues.

It is entirely random and started today even though I haven't driven the vehicle in a month. It has no effect on the battery because as stated before it will continue even with the battery removed. It will makes the noise from hours to days, cease then begin again. All systems of the vehicle operate normally.

Any ideas?

 

if possible, you may want to upload a small video clip of the noise to get a better response from forum members.