how to diagnose a bad P.S. pump

Question

Got a 95 dodge intrepid that has a whining noise that makes itself really noticeable when you press the accelerator, problem is i can't pinpoint the exact location and since the water pump, alt, and power steering are all in the same general location, even using a hose to listen to each part does not reveal where the noise is coming from although it seems to be from their general location/area.

Pulled serpentine belt and cranked the engine and and revved it to see if the noise would still be there but it was not. This makes it appear to be one of those three components that is causing the noise.

had the alternator tested and it appears to be fine and did not make any noise whatsoever on the testing machine. since a water pump is only $30, I may replace the one in there just for prev maint and put a new serpentine belt on and crank the car to see if noise persists. if it does, i'm left to consider the power steering pump.

is there a failsafe way to diagnose the pump as the source of the noise? i might add that since I've had the car, I always thought the steering required a little too much effort, compared to other cars I've driven.

the old serp belt has lots of little cracks but still seems to be in good overall condition. i highly doubt that could be the cause of a whine that has a real mechanical type ring to it, like it involves metal.

it's possible my rack and pinion is the problem and the pump may not be, but has anyone ever had a rack and pinion make a whining noise that really jumps out at you when you push the accelerator and at idle you can hardly notice it??

I do notice that with the serp belt off, the power steering pulley doesn't rotate freely like the water pump pulley does. i can turn it easily but it doesn't spin, it just stops once i stop turning it. is this normal? if not, i suspect dirt/oil/goo may have caused this because this area of the car has alot of dirt/oil/goo mixture on things, not good I know.

Appreciate any helpful advice on how to test my power steering pump to make sure it's within operating parameters.

JR Lomas · Accepted Answer

I just got an automotive stethoscope for $8.99 at autozone.  Get one anlisten to your engine, you will pinpoint the problem in no time.  Best $9 Iever spent.- JR

Daniel M. Dreifus · Answer

Power steering pumps are pretty straightforward in their operation, basically a spinning disk with vanes. Usually just a matter of checking for leaks. Have you checked the condition and level of the power steering fluid? It can ususally be flushed by removing a line at the reservoir, or drawing out fluiid with a turkey baster, turning the steering lock to lock a few times, and then repeating several times.

Dan · Answer

I recently had a very similar situation with my wife's '97 Sentra. The engine would make a squeaking sound at idle, which would disappear when you got off idle speed. From the nature of the sound (bearing-like), I figured it had to be one of the accessories or less likely maybe some part of the timing chain mechanism. Since it didn't change at all with electrical load, and since having the AC on or off made no difference, I decided it had to be the water pump or the PS pump, leaning toward the latter due to the pitch. I noticed the sound was worse in the rain, so I got a spray bottle & with the car in the air carefully directed some water at the front PS bearing while the car ran. Sure enough, it started to scream like made. As a further test (since the pump is about $160) I sprayed a bit of oil on the same area & the squeak stopped. Put on a new pump and all is fine. In this case, the sound was the front bearing, had it been an internal noise these tests would probably not have uncovered the trouble. BTW the sound itself was very elusive in terms of location; I have a stethoscope & even with it pressed right against the PS pump next to the bearing I could not tell for sure that was the source.

Dan

<SHERNDON1 · Answer

put a metal rod like a socket extension against each component and your earagainst the other end, will work like a stethoscope

mZ · Answer

actually a piece of hose works better for my situation. i think it might be the water pump as it turns out. when I spin the pulley with my hand i can hear the spin is not smooth, there is a little grinding going on and with the belt on and engine running, i can see a slight wobble of the pulley perpendicular to the pump shaft (in and out) and the hose in a certain location (right behind the pump) seems to be the loudest location with regards to the noise. well, looks like I'll be changing that pump out.

i guess at 123k it's due for a water pump change anyway, plus a new thermostat and few hoses to boot.

how to diagnose a bad P.S. pump

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