Hey everyone,

The polo has recently developed a new noise. It's started to whine (and unfortunately it's not a G40 haha). The noise is often heard when pulling away or changing up the gears at a low rpm. However, the noise is most audible (and annoying!) when changing down into 2nd gear I have noticed but I presume any aggressive downshift would result in the same. I thought that this might have been a clutch related noise however even when fully off the clutch, the noise continues for a few more seconds.

I've done some general reading around and have come to a few possible answers that I'd like clarification on as to whether they could be the solution.

 

Change of gearbox oil?

Contaminated or damaged clutch?

A worn or damaged belt?

 

Any advice or notes from previous experience would be helpful.

 

Thanks guys!

Low gearbox oil level?
 

if you are stood can you hear any whining noise with it in neutral? If so depress the clutch, if it disappears then likely to be a gearbox issue.

44 minutes ago, mk2tastic said:

Low gearbox oil level?
 

if you are stood can you hear any whining noise with it in neutral? If so depress the clutch, if it disappears then likely to be a gearbox issue.

Just checked, no whining while idling in neutral. It's dead silent. It was very loud when just driving with the heater on however. Could that be linked to something?

So can you only hear the noise when moving, or can you hear it whilst idling or revving the engine at a stand?

I can’t see it being heater related, unless it’s actually a slipping alternator belt or an alternator issue which occurs when on load(heater on). See if you can replicate the noise when you have all the electrical equipment on, like headlights, HRW, heater etc. Then turn them all off and see if it is still there. If it only occurs with the heavy electrical load then check your alternator belt and alternator. Normally a slipping belt is more of a high pitch squeal than whining though. However a dodgy alternator can whine and are usually worse on load.

 

My heater used to howl on setting 2/3 due to dry bearings, but that noise was obvious as it only occurred with the heater on and was emanating from the middle of the dash.

Edited 8 January, 20233 yr by mk2tastic

23 minutes ago, mk2tastic said:

So can you only hear the noise when moving, or can you hear it whilst idling or revving the engine at a stand?

I can’t see it being heater related, unless it’s actually a slipping alternator belt or an alternator issue which occurs when on load(heater on). See if you can replicate the noise when you have all the electrical equipment on, like headlights, HRW, heater etc. Then turn them all off and see if it is still there. If it only occurs with the heavy electrical load then check your alternator belt and alternator. Normally a slipping belt is more of a high pitch squeal than whining though. However a dodgy alternator can whine and are usually worse on load.

 

My heater used to howl on setting 2/3 due to dry bearings, but that noise was obvious as it only occurred with the heater on and was emanating from the middle of the dash.

Yes the noise is only when I'm moving, haven't heard it when revving stationary or idling.

I had heater, wipers and lights on today and it was more prominent than running this afternoon with absolutely no electrics on. I think it is more of a squeal as in the car sounds like it is crying out?

My heater also howls through all settings when on and yes it is obviously coming from the dash.

The squeal under load however comes from within the engine bay.

I'm not sure it describes all of the symptoms, but could it be wear on the gearbox synchro?

The way to eliminate the alternator and belt is to remove the belt and take it for a short drive, see if the noise stops. Word of caution with trying this though, make sure your battery is in tip top condition and only drive for the minimum amount of time/distance to establish if the problem persists or not. You don’t want your battery to die whilst out on the road!

11 hours ago, mk2tastic said:

The way to eliminate the alternator and belt is to remove the belt and take it for a short drive, see if the noise stops. Word of caution with trying this though, make sure your battery is in tip top condition and only drive for the minimum amount of time/distance to establish if the problem persists or not. You don’t want your battery to die whilst out on the road!

Well, I drove to college this morning with absolutely no electrics on, and the noise was not there. The car was obviously cold from over night so I didn't rev the hell out of every gear but I did give it a good run down one of the straights with no noise in any gear. Pulling away created no noise either.

Seems likely to be alternator then?

I’d certainly check the alternator belt and tension as a precaution. There should be very little play in it when you press it down in the middle of it’s run, 1/2 inch max deflection.

 

 

1 hour ago, mk2tastic said:

I’d certainly check the alternator belt and tension as a precaution. There should be very little play in it when you press it down in the middle of it’s run, 1/2 inch max deflection.

 

 

Had a look underneath and noticed the little tensioner underneath. The bolt was loose! So we tightened it up and it hasn't made the squealing noise at all yet.

Also tested the voltages with car idling and when increasing revs both with all electrics on and all electrics off. It now holds a steady voltage.

Thanks for your help!

Glad you seemed to have found the problem and it was a cheap  easy fix.

 

 

 

 

Just as an aside, on a freshly charged battery you can start the car (Coupe GT) and drive from Leeds to Ambleside without running out of electricity. It will also do 3 starts and an hours driving without the voltage dropping below 12.

3 hours ago, mr brightside said:

Just as an aside, on a freshly charged battery you can start the car (Coupe GT) and drive from Leeds to Ambleside without running out of electricity. It will also do 3 starts and an hours driving without the voltage dropping below 12.

Well thank you that's good to know. Shame I don't have a GT 🥲