1999 Ford Explorer humming

[bri888]

Hi everyone!
I just got a 99 Ford Explorer. It has a humming sound. I know it must be the power steering but it hums when it is idling. Not sure what's happening.

 

[Mbrooks420]

Why do you know it must be the power steering? If it’s making the sound and you blip the throttle does it disappear?

 

[8TZX]

I experienced humming on my '99 5.0L. It was the Idle Air Control (IAC) valve. Easy to replace and not expensive.

 

[EB4X]

Is fluid on low side, slow leak..... if so Lucas stop leak works great and lubricates system, stops squeals and rough spots in steering...buys time before having to replace pump. Not snake oil.

 

[J_C]

I'm thinking same as others, check steering fluid, check whether noise changes with engine RPM, try cleaning out IAC if it hasn't been done recently, and see if you can isolate source looking at pulleys, possibly pull the belt off to see if the noise stops so must be a belt driven component.

Don't run it long with belt off since the alternator won't be charging the battery. I'd even think about charging the battery beforehand, instead of running the engine to top it off, so the engine isn't hot while getting the belt off. Granted it should only take a minute running IF the noise is always there from the moment of startup.