Faint whirring / whining sound

[Dr Mike Oxgreen]

Hi folks...

I've been noticing a new engine-related sound recently, and it would be nice to hear what you think it could be.

It could be described as a whirring or whining sound, which is only audible with the roof off and seems to be coming from the engine bay. It rises and falls with the engine revs, so I'm convinced it is engine-related rather than transmission.

In fact it sounds very much like a supercharger, but in reality it is likely to be a bearing on its way out.

At the moment it's not worrying me enough to stop driving the car - my gut feeling is that it's one of the engine ancillaries like the water pump or alternator.

What do you think is most likely? Water pump? Alternator? Santa's fairies have brought me a supercharger as an early treat? What else might it be?

Any ideas on how I could diagnose the source of the noise?

[Harrytsg]

To be honest it could be any of those, as well as the belt itself. The belt comes off easy enough, check that for cracks on the inside or frayed edges, then with it off grab all the pulleys and see if any move, wobble or don't feel smooth in rotation.

It should only take 5-10 minutes, your tea won't even go cold while your doing it.

[Dr Mike Oxgreen]

Thanks Harry, I'll do that if it stops raining!

Is there a technique to removing and refitting the belt, or is it just brute force?

[Harrytsg]

Here's a YouTube link on how to do it, 46 second off then on!

http://www.youtube.com/watch?v=kfIg2afMts8&fea...

[Dr Mike Oxgreen]

Perfect! So it's just a case of pulling the tensioner pulley up. Oh, and probably a good idea to take a picture first so I can remember the belt's routing. Now I just need it to stop raining - not going out there at the moment for fear of drowning.

Edited to add: It stopped raining for several seconds, so I pounced on the chance. The routing of my belt and the positioning of the tensioner is slightly different from the video due to aircon (my tensioner had to be pushed downwards rather than upwards), but otherwise it really is as simple as it looks.

Everything feels firm and smooth, and turns freely: water pump, alternator, aircon, PAS. And I couldn't feel any play in the bottom pulley either.

I fired it up and held the throttle part open, and to be honest I couldn't hear any whirring at all. So it could be a case of automotive hypochondriasis.

Edited by Dr Mike Oxgreen on Sunday 4th November 10:08

[MADMAX2]

Mike try listening around the alternator area if the bearings inside are on the way out they start whirring or whining.. just increase the revs it should sound like a spitfire plane type noise.. if so you need to recon the alternator or get a new one.

[fausTVR]

Mine makes a whistley/whiney sound in time with engine revs when engine cold, then gradually disappears as it warms up. Never had a clue what it is though.

[Dr Mike Oxgreen]

I've decided this definitely isn't my imagination, so I'm still pondering what it might be.

On the way home tonight, I thought it could be low PAS fluid, so after letting it settle I checked it. Sure enough, the fluid is only just touching the bottom of the little dipstick.

So, what should I top up with?

And what should the level be? The dipstick has two "steps" on it - should I top up to the upper step?

Another thing it could be is low refrigerant in the aircon. My SEAT makes a whirring noise when it needs regassing, but that stops instantly when I turn the aircon off. Does anyone know if the TVR aircon system would make a noise when low, even when it's turned off?

Edited to add: The Opie Oils web site suggests this; what do you reckon?

Edited by Dr Mike Oxgreen on Thursday 8th November 18:49

[DastardlyDick]

Mike - my guess would be alternator. I had exactly that sound and it turned out to be alternator. I took the car to my local 4x4 landrover independent and his mechanic put some form of measurement thingy on the battery and then on alternator (whilst engine was running) and announced that alternator was on last legs and not charging battery adequately. I ordered a replacement via him ( Denso @£120 as opposed to £450 quoted by LandRover main dealer! When it arrived turned out it was exactly same Magnetti Morelli unit that was originally fitted to car anyway - also sent old unit to be refurbed for £50 to have as replacement). Whilst waiting for replacement, diagnosis was shown to be correct as battery warning light started coming on. New alternator arrived and fitted and all OK now with noise gone. Good lucksorting your problem. Richard.

[Dr Mike Oxgreen]

Thanks for the suggestions, folks.

I'm pretty sure I've fixed it: it was just the PAS fluid that needed topping up. Bought some Halfords "Advanced" auto and PAS fluid which said "Dexron III" on the bottle. I woz tempted by a set of Ripspeed wheel trims that'll look well mint innit, but I'll have to wait for my next giro.

Test drive with roof off in the drizzle, and no whining - yay! But I can no longer pretend to have a supercharger - boo!

[Harrytsg]

Great news on your success, what you need now is one of these........

iPhone/iPad URL:
Turbo Sound Exhaust Muffler Pipe Whistle Fake Blow-off BOV Simulator Universal

Browser URL:
Turbo Sound Exhaust Muffler Pipe Whistle Fake Blow-off BOV Simulator Universal

Super charger whistle is so passé.