Loud hissing/ air leak sound

[longshooter]

I own a 2006 Ram 2500 with the 5.9/ auto trans. Totally stock. 175k miles on it. I was towing my boat (about 6k lbs) over a mountain pass last weekend when I heard a hissing sound coming from under the hood. It wasn't the normal turbo whine, it was louder, like air leaking from the intercooler. No loss of power and only under load, when the fan clutch engaged. All my intercooler connections seem to be tight but the hoses are probably original. Has anyone had this problem or a clue of what may be causing the noise? Thanks in advance.

 

[Crunch]

I own a 2006 Ram 2500 with the 5.9/ auto trans. Totally stock. 175k miles on it. I was towing my boat (about 6k lbs) over a mountain pass last weekend when I heard a hissing sound coming from under the hood. It wasn't the normal turbo whine, it was louder, like air leaking from the intercooler. No loss of power and only under load, when the fan clutch engaged. All my intercooler connections seem to be tight but the hoses are probably original. Has anyone had this problem or a clue of what may be causing the noise? Thanks in advance.

Does your cruise control still work? If not, there is a good chance the vacuum line split open or broke.

 

[B.G. Smith]

The turbo winds up tighter at high altitude and under load? Also might look at the belt and drive pulley on fan and crank, if the grooves are shiny at the bottom the belt or pulley may be worn out. No vacuum on 06. bg

 

[cerberusiam]

Sure it wasn't a belt slipping? How much throttle and boost did you have at the time you heard the odd noise?