Hey guys, i have a 2005 dodge ram 1500 quad cab with the 4.7L engine. I've been hearing a very faint electrical/metalic like sound coming from the engine compartment but couldn't tell where it was coming from until tonight. It's very hard to explain this sound as I've never heard anything like it before. The noise has gone from faint to somewhat loud. I opened the hood of the truck tonight and at first it sounded like it was coming from the radiator. I splashed a very small amount of water on the belt as the truck was idling and the sound went away but within a couple of minutes the noise came back. The belt seems to be in good shape and even if its not it doesn't seem right to me for it to make this sound.

A little history:
I had the water pump replaced last summer. And about 6 weeks or so ago I had the radiator flushed as my truck started over heating. The mechanic found that it was VERY low on coolant even though I have no coolant puddles under the truck and the passenger side of the radiator was much cooler than the right side. He flushed it and said I may need a new radiator.

Also when starting the truck up in the morning I can hear what sounds almost like liquid running through some kind of line. Maybe some air pockets running through the lines making this sound? Seems to go away after revving it some.

My main concern is this noise coming from the front of the engine but any and all advice would be great help!

 

Regarding the sound of rushing water, if you hear that inside it's the sound of coolant flowing through the heater core, but there is an air bubble due to low coolant or just trapped air, so you hear water rushing around in that air pocket.