High pitched whine, whining noise

Hi, noticed the last few days I can hear a high pitched whining noise, from the engine bay I reckon (300tdi). I can only hear it when the engine is under load or decelerating, seems to be definitely engine speed related rather than road speed, if I slip it into neutral and coast there's no whine and it's not related to the clutch being in or out. We've had the stereo on a very low volume for a few days and at first I thought it was interference from the ignition but today I turned it off and the noise was still there, it's not really loud but it is noticeable and the wifey can hear it and she knows nowt about engines and how they should sound! Seems more pronounced the higher the revs, when we got home I tried with the car stationary and it was hard to hear it til revs were up to about 2.5k - 3k, first there's a hiss which I assume is the turbo then comes the whine......any suggestions, advice? I haven't yet had a listen directly, with the bonnet up but I now have paranoid fears of turbo bearings being shot and other such serious stuff...

A friend had similar problem & it turned to be the bearing gone in the alternator.....or have you tried driving without the wifey in the car...maybe the whining will dissappear !!!

Ah, you know her? That's why, usually, the radio is turned up!
Since I posted I wondered about the alternator. Other thought I had is that I've really just noticed it since I changed the air filter the other day...

you sure it's not just turbo whistle? should be delievering full boost about 2-2.5k revs

you could test for play/sticktion in the alternator and water pump, just use a 15mm spanner to lift up the tensioner roller and whip off the belt. then turn them by hand... the bearings should all be smooth.

a large long screwdriver or length of broom handle works well as a stethascope: try placing it on different areas of the engine see if you can hear it through that!

The most obvious and common screeching noise generater is the idler pulley bearing and assembly.

To check for this, slacken the fixing bolt and slip a penny or similar sized washer between the engine and the idler assembly at 9 'o clock, then retighten fixing bolt.

This is an odd-sounding but well-know trick for Tdi 300. I know it sounds daft - but it DOES work.

Cheers & good luck

Dave

I had a similar noise that went from being a high pitched whistle to a gushing blowing whistle. I also started to loose power on the motorway but was OK around town at low speeds.

Turned out to be a split turbo hose, £37 later and the problem was fixed.

If you've just replaced the air filter, a/ you might not have put everything back together properly, or b/ it might be that the improved airflow is making your turbo whistle louder.

thebiglad said:

The most obvious and common screeching noise generater is the idler pulley bearing and assembly.

To check for this, slacken the fixing bolt and slip a penny or similar sized washer between the engine and the idler assembly at 9 'o clock, then retighten fixing bolt.

This is an odd-sounding but well-know trick for Tdi 300. I know it sounds daft - but it DOES work.

Cheers & good luck

Dave

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just did that trick yesterday... and yes it does work!!

Could be your viscous fan also known as the fan clutch, while the engine is switched off can you move the fan if its really hard to move then its the viscous unit which will need replacement as your mpg will decrease.

After 2 new belt pulley tensioners in a year i did what THE BIG LAD said and it worked as well although funnily enough mine was only noisey after start up for a minute. The whistling noise sounds as if you are NOW after replacing the air filter getting full use out of the Turbo and she's singing with pleasure after having a hesion sack over her head for an age. Take out the filter altogether for a day in the dry, clean out the box altogether and drive her along the dual carriageway for a few miles this will make the sound more pronounced, good idea to put a thin bit of cloth over the intake to stop big bits of sheite getting in but the turbo will sound louder and you can identify if it,s a similar sound. phew.

Thanks all for ideas and suggestions I have lots to try now Did my engine oil, filter, and fuel filter yesterday and noticed on a second proper listen that it's more of a whistle than a whine and I can hear it more at low revs than I first realised. It seems to be coming from the central to left hand side area of the engine bay, kind of around the fan area or a bit over towards the air con init. Can't quite pin it down! Might be nothing really but it's bugging me now that I've noticed it!

sp33der said:

Thanks all for ideas and suggestions I have lots to try now Did my engine oil, filter, and fuel filter yesterday and noticed on a second proper listen that it's more of a whistle than a whine and I can hear it more at low revs than I first realised. It seems to be coming from the central to left hand side area of the engine bay, kind of around the fan area or a bit over towards the air con init. Can't quite pin it down! Might be nothing really but it's bugging me now that I've noticed it!

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try the penny trick!

A simple question... Have you checked the belt tension. Maybe the belt is simply slipping.

Louis

i had a high pitched squeeling and got the idler pulley assembley changed this cured the squeeling for a few months but now it's come back ten times worse...

only under load if it's idling no problem...So i'll try the penny trick tommorrow and see if that cures the thing... it;s got that loud that even with the radon on it can be heard...

checked your turbo pipes yet? they are to the left of the engine (when looking from the drivers seat)

Okay good afternoon Gents,

The penny trick has worked!!!!
I will take it out on a run later to see how it does under normal loads, mine was that bad it sqweeeeled under idling.

So the test will be when it's running at 3k revs...

Anyone know best place to get a recon rad for a 300tdi 94 plate? then i have to sort out the bot floor once and for all....

Not done anything to mine yet, too much work! It may indeed just be my turbo singing with happiness after I changed the extremely...extremely...extremely mucky air filter. It's not screeching, it's definitely a whistle, just since I changed the filter and the car certainly seems to have a bit more zing to it. I am heading oop north to Newcastle on Saturday so I'll see how I get on with a 300 mile drive...and then another 300 back on monday!

well i can say the trick has worked i have ben driving it all over the place and not a sound out of place..

a great trick.......thanks biglad!! brilliant

sir Adrian said:

well i can say the trick has worked i have ben driving it all over the place and not a sound out of place..

a great trick.......thanks biglad!! brilliant

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Hi sir Adrian, it was my very great pleasure. I know it sounds daft, but it works doesn't it.

There must be some alignment issue that the penny sorts out, but it's poor of LR not to have found a better solution themselves, they are engineers after all

Cheers
Dave

sp33der said:

Not done anything to mine yet, too much work! It may indeed just be my turbo singing with happiness after I changed the extremely...extremely...extremely mucky air filter. It's not screeching, it's definitely a whistle, just since I changed the filter and the car certainly seems to have a bit more zing to it. I am heading oop north to Newcastle on Saturday so I'll see how I get on with a 300 mile drive...and then another 300 back on monday!

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Hiya sp33der, you can buy new airfilters from these people as part of a filter kit (£6+vat):

Filter Kit - Disco 300TDI

Hope you had a pleasant & uneventful weekend up north.

Cheers
Dave