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whining power steering pump?

22K views 13 replies 6 participants last post by  fatboytx 
#1 ·
Ok so....2008 F250, 6.4L FX4, 115,000 miles. It's making a whining noise (rrrrrear) that increases in volume with acceleration. My first thought was power steering pump. However, steering seems normal and no kickback from the hydro boost brake system. Not a big difference in the noise when I turn the wheels. I started off by flushing the fluid with Mercon V. It was only slightly dirty but did smell a little burnt. That did nothing at all to quiet the noise. I decided I would go ahead and replace the pump but when I got to talking to the kid at the parts store, (he actually seemed pretty knowledgeable) he talked me into thinking it was the six month old alternator going bad. It was a remanufactured alternator. I just finished replacing the alternator again, and of course I still have the same exact noise I started with. So I guess my question is, should I go ahead and replace the power steering pump even though the steering and brakes are functioning just fine? I think I could tell the difference in noises if it was the pulley bearing going bad. Thanks for any and all replies!
 
#3 ·
Yeah... tried that. I am not one to replace parts to find the problem either, which is why I am on here looking for helpful replies. Sound seems to be coming from power steering pump. Alternator was replaced because it tested bad due to a failed voltage regulator.
 
#4 ·
You did a complete flush of PS? No change in sound or anything? I copied these notes from another thread but you can find youtube help for this. If I had a noisy PS pump I'd first try doing a flush before I replaced it.

"The way I have done them is by taking the cooler hose beside the radiator loose and running the hose down to a drain pan. Turning the wheel back and forth a few times with the front end jacked up will purge most of the fluid. After draining, fill with fluid and start the engine. Then turn the wheel a few times, step on the brake pedal a few times, turn the engine off and check/add fluid as needed."
 
#5 · (Edited)
I just had the same noise's. Not long after, turbos went out.
I even checked fluids in steering pump twice thinking it must be coming from it.
I hope that's all you have and just a strange coincidence.
 
#7 ·
There is only one thing that sounds like a power steering pump .......
 
#9 ·
A power steering pump. It's whine is very distinctive.
 
#10 ·
I agree, it is very distictive. And I'm familiar with that sound.....but the steering is smooth and the noise does not increase or decrease when I turn the wheel. that's what has me stumped. However the noise gets louder with acceleration. Also gets louder if I'm in park and Rev the engine. The noise is very responsive with the accelerator. More pedal...more noise. Less pedal...less noise. Even slightly feathering the pedal will increase and decrease the noise. ???
 
#11 ·
Then I would pull the belt and restart to see if it's turbo related or a belt driven noise.

If not turbo since the belt is off you can spin the components and pulleys to see if you can determine the source. The idle pulleys and tensioner pulleys are cheaply and easily replaced rather then buying the entire part.
 
#14 ·
Any update? Have you ever changed belts on the truck? If you go component by component and listen to it ... with a mech stethoscope ... and none seem to be making a noise then I'd inspect the belt tensioner pulley(s). If you search you will find pics of what to look for when a pulley separates.
 
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