Whiney Noise with Acceleration

[DerekA]

In the last week an extra noise is coming from engine bay which starts on engine start and goes up and down with accelerator pedal. Does it in Park and Drive.
More pronounced when engine cold (notably last night - UK temp minus 4) and fades as engine warms, but doesnt go away.
In the car, it sounds like some sort of hydraulic arm being activated (think mobile platform being raised or even an electric fork-lift). Smooth but whiney, not clump/thump nor mosquito high pitch.

Lifted bonnet and it seems to come from the part circled red in attached picture.XC90 Engine Bay 1.jpg

I'm not sure what this is, although I can see a belt rotating.

Can anyone tell me what the part is, is it the type of part that could make the noise I describe and if so what remedy I am looking at.

I hate going into a garage without knowing what's up - always feel I'm writing a blank cheque! - so any thoughts/pointers or specific directions would be warmly received.

Thanks

[jamie1131]

That's your power steering pump. Have you checked the power steering fluid level?

[CaerYnArfon]

Agree with jamie... I had almost exactly what you describe. (If you are old enough) the sound reminded me of an old AM car radio with no condenser on its power line...

I tracked it to the power steering fluid being virtually empty. Cleared out the old stuff (see CheshireD5's video Here how to do it) topped it up and hey presto sound was gone :-)

Easy job to do...

[DerekA]

Thanks both - will try Power Steering fluid change when I can - video link v.useful. I am not 100% convinced it is the steering fluid as the noise starts upon ignition and raises and lowers with engine revs whilst in Park (and drive), with no movement on steering wheel. Hope I am wrong and you are right as it will save a bob or two in garage investigation time. Will report back. Thanks!

[owenfackrell]

It may well be the alternator bearing failing which sits just under the power steering pump.
They whine when they go. If the pulls clutch is working you should be able to hear a slight lag in the noise slowing down verses the engine.

[oragex]

The alternator bearing may fail at higher miles, but it will start will low noise and increase during a long period of time.

What OP is describing does indeed point to the power steering pump perhaps low in fluid (possible leak at the hoses) or simply wrong fluid not working properly on colder temperatures. If the fluid is wrong the pump will make noise even if the steering wheel is not turning. That is because the pump is running at all times.

As the OP appears not to have knowledge in mechanics, I'd recommend being aware of bringing the car to a mechanic that will suggest starting to replace parts. The very easy thing to do is get a hose and touch one end on the power steering pump - careful about the rotating pulley and belt just nearby - and keep the other end of the hose to the ear.

Most likely, as pointed by 2 or 3 other members, the fluid is wrong or low in level. Check all connections of the hoses underneath the reservoir and at the pump, tighten if needed. The fluid should have a light green color, only Pentosin fluid should be used.

By all means don't let a garage replace the pump before making sure the fluid is the correct type and at level.

[laundryman]

Originally Posted by DerekA

In the last week an extra noise is coming from engine bay which starts on engine start and goes up and down with accelerator pedal. Does it in Park and Drive.
More pronounced when engine cold (notably last night - UK temp minus 4) and fades as engine warms, but doesnt go away.
In the car, it sounds like some sort of hydraulic arm being activated (think mobile platform being raised or even an electric fork-lift). Smooth but whiney, not clump/thump nor mosquito high pitch.

Lifted bonnet and it seems to come from the part circled red in attached picture.Attachment 109129

I'm not sure what this is, although I can see a belt rotating.

Can anyone tell me what the part is, is it the type of part that could make the noise I describe and if so what remedy I am looking at.

I hate going into a garage without knowing what's up - always feel I'm writing a blank cheque! - so any thoughts/pointers or specific directions would be warmly received.

Thanks

And ther was me going un PC to comment" leave the wife at home"!!

[DerekA]

Thank-you all - it would appear it was indeed the power steering fluid. Do I congratulate those who clocked this straight away or my superb description? Since addressing this, the noise has not returned so hopefully that's a tick on the box.

Now to tackle rear discs & pads and find a garage who'll do the timing belt for a good price ...

Thanks all.

[deepsix]

I regularly get whining from the passenger seat if I accelerate too fast.

[Carrizos]

Ye I get that whining occasionally too or cheering if it is one of my kids in that seat. Just changed the belt tensioner and idler, checked all pulleys when tension was off, all good apart from the power steering one which has a tiny bit of play. No sign of weeping and steering is fine. Is it OK to just replace the pulley or should I be thinking of changing the complete pump?