Buzzing/whirring sound driving me insane

[tommyabward]

Could use some advice concerning a buzzing/low-pitched groaning noise that just came up yesterday on my 03 Qx4 (88k). I've been having start up issues, so I immediately thought fuel pump.. but the sound is coming from driver's side of the engine compartment -- which is what confused me. Comes on about a second after the motor turns over-- idling and at speed. Pitch also increases in tandem with RPMs. Videos attached below.

Youtube - https://www.youtube.com/watch?v=KzY6dFWYVVk , https://youtu.be/bY1dWp--VrY

Any help is greatly appreciated. Thanks in advance.

[fleurys]

There is 3 things that could do this noise...

1) Power steering pump
2) AC compressor
3) Alternator

All 3 are belt driven with the engine, so this is why the sound changes with the rpms. Now, I saw in your second video that the AC and fan were off. For me this rules out the AC compressor.

Usually an alternator that goes bad will have a more higher pitch than that. Therefore you are left with the power steering pump. You could confirm it by inserting a long screwdriver or piece of steel or aluminium bar between the pump and your ear.. This will amplify the noise and either confirm or not that this is the issue. You have to be carefull not to touch the running fan blade while you do this...

Before you change anything, make sure your powersteering fluid is full.

[rgk]

PS pumps make exactly what you describe: a buzzing, whirring, groaning noise. Check whether the noise gets louder as you turn the steering wheel at idle.

Pumps usually don't go bad, the more likely issue is air in the line. Check your PS fluid reservoir for air bubbles or foaming. It may be time to replace all the clamps on your PS hoses. Check for PS fluid leaks. PS fluid is trans fluid, so look for a red or brown fluid that smells like crayons (if good) or cigarette butts (if bad).

I had one weak clamp at the top of my (Subaru) pump, which connected the intake line to the pump, that was causing a lot of noise. As soon as I replaced it, the noise went away completely.

[tommyabward]

Update, it was in fact the alternator ... Planning to replace this weekend.