Hey all - 2000 Explorer Sport, 94,500 miles. RWD, 5-speed manual.
The power steering pump is making the familiar moaning sound...definitely the pump as it changes pitch when the steering wheel is turned. It is audible with no load on the pump at all. Is there anything I can do to quiet it down short of replacing the unit, and does this mean my pump is about to explode?
Before you do anything, stand outside your vehicle and have someone else park it in the driveway. Pay attention to the noise it makes. Then go hang out in a busy parking lot and wait for another Explorer to come by. In fact, listen to ALL the Fords that come through. I say this because Fords are notorious for noisy PS pumps. Yours might just be making the 'normal' noise.
Part of the noisiness is due to the plastic housing on the pumps, and there's not a whole lot you can do about that. (I've often wondered about blasting my PS pump with some of that rubbery undercoating stuff, but I don't know what sort of heat issues that might cause).
IIRC, i once read on this ng (or maybe it was alt.trucks.ford) about a PS fluid (or additive, can't remember which) that Ford developed to quiet the PS pump. Never tried it myself, don't know how effective it is. I just deal with the noise.
I've also heard of people adding an additive (not sure about getting it from Ford though) that will quiet a noisy pump. I've also heard of people putting in a synthetic Dexron and having good results. I've never tried either one. Depending on how quiet you want it, Ford has issued a TSB on noisy power steering pumps and if you buy your rebuilt pump from Ford, it will probably be quieter than the one you take off. However, I've seen "lifetime" rebuilt pumps from some of the national chains that are noiser than the ones that they replaced. I guess the national chains don't put a guarantee on the noise that they produce........
I have had this problem with almost every Ford PS pump I've owned over the last 25 years. For the last several, I have found that flushing and filling with Dexron and adding 2 oz of Lubegard red will quite them right down to almost dead silent. The noise is caused by either cavitation because of air entrained in the fluid or the relief valve chattering. I do not know if the Lubegard works by reducing the air entrained in the fluid or some lubricating ability but, it has worked on every one I've had over the last 15 years. There are other similar additives but, I have not used any of them since I am basically additive resistant in nature. The synthetic Dexron may work the same way since it probably has different additives. I would not replace the pump before trying the flush and additive - I have replaced several with negative results.
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