[James Nygren]

I just bought a 2000 F350 7.3L with 183,000 miles. It is pretty much stock other than the exhaust and suspension lift.

I have a loud hum or growl at idle that goes away with an increase in RPM. If I turn the steering wheel the sound does not change and the PS pump does not make any noise when turning. Not sure where to start. Any pointers?

 

[RT]

Take your fan belt off and see if the noise goes away. If it does, spin each component manually with the belt off listening / feeling for bearing noise. The tensioner and idler pulleys are frequent culprits, as is the water pump. Alternator and a/c compressor bearings can be at fault as well. Most of those can be rebuilt as opposed to replacing - the water pump being the exception.