What is this NOISE?????

[03SonicSnake]

My mom's 99 F150 5.4L is making a strange sound during acceleration. It would almost sound like it would have an eaton supercharger whining just like a lightning does. You can barely hear it in the engine bay, but big time inside the truck. Like something's spinning really fast or something. It will do it on heavy acceleration and sometimes even with just a constant throttle at any rpm or speed. As soon as your foot comes off the gas, it stops though. I need you guys' help with the 5.4L trucks, maybe someone has a clue or suggestion. Oh and no check engine light either. The only thing I can think of but probably isn't related is that the ABS light has been turning on and off every once in awhile. Thanks in advance guys!!!

Jason

 

[Skrapmetal]

Have you tried turning the radio off (not just down)?

My old ranger's speakers whined at pace with the engine RPMs due to a bad ground, sounds like what you're talking about.

 

[Nvr_Spds]

EDIT: Skrap beat me to it.

 

[Scuba-Matt]

Power steering pump?

 

[Dusten]

I Am with the two posts above me, sounds like a bad stereo ground, but maybe not if you can hear it in the engine bay

 

[Scuba-Matt]

I skiped over the not as loud in the engine bay.

 

[03SonicSnake]

hmm

The radio was not on during the noise. Also the power steering fluid reservoir where you add fluid, the fluid that was already in there was kind of churning similar to the intercooler reservoirs on the 03-04 cobras when the pump turns on. Is that normal?? I'm leaning toward the power steering pump going out, because she also told me that before that noise started it just sounded like a hissing noise, kind of like air escaping or something. Any more thoughts??

 

[00 white lightn]

I would think, PS pump, maybe water pump bearing, idlers. You mentioned a hissing noise. I am not too sure. Since it only does it noticeably inside the vehicle. That pretty much rules out the bearings ect. Unless they are making noise at low RPM's. And when under load, the noise increases. Check all the pulleys and see if anything is on them sometimes you can get something on the belts and it causes a noise. But like some of the others posted. The radio is a likely cause, turn it off and see if it keeps doing it. You can always take it by the dealer or call and ask a ford tech what he would think it would be. And yes the PS resevoir will have some movement to it from flow. Ever truck i have seen has done it that has the little view window in it. If the noise increases and decreases with rpms. It is probably an idler, PS pump whine, or a bad bearing on the water pump.

 

[Skrapmetal]

The radio was not on during the noise. Also the power steering fluid reservoir where you add fluid, the fluid that was already in there was kind of churning similar to the intercooler reservoirs on the 03-04 cobras when the pump turns on. Is that normal?? I'm leaning toward the power steering pump going out, because she also told me that before that noise started it just sounded like a hissing noise, kind of like air escaping or something. Any more thoughts??

Just for the hell of it, check it out and make sure the radio is *OFF*, not turned down. I know, you said it was off... but there was a guy here just a few days ago that was asking about a whining sound that said it was off, but it was actually only turned down.

I can't think of anything else that would whine loudest inside the cab.