I have a 62 plate mk2 Octavia facelift 1.6 CR TDI and have noticed recently that, when driving, or accelerating between 60 and 70mph, the engine noise increases to the point it's distracting! Up to, and after these speeds noise goes back to 'normal' and  is fine. There doesn't appear to be any change in performance, it's as though I've started driving on rougher tarmac, Any ideas what this could be. Orange oil top up light came on, and it did need oil, however even after topping up this issue still persists! Any help greatly appreciated. Thanks.👍

Is the noise purely related to road speed or engine speed?

Also does it occur in all of the higher gears or just one?

Hi Liger 1956, Noticed the issue when on the motorway, not noticed on any other journeys as yet. On pressing the accelerator at speeds between 60 and 70mph, the normal 'hum' of the engine becomes louder, even when maintaining a steady speed between these 2 figures, once above 70 or below 60 the engine sounds as normal.

Did you drop down a gear to see whether the noise reduced?

No I didn't to be honest, might just take it up the road this afternoon and do exactly that. I'm guessing you may have an idea of what it is!?🤔👍

I have no idea what it could be at the moment. I am just trying to reduce the number of variables so that I, or another member, can suggest what it might be. Remote fault finding is difficult at the best of times.

 

Your noise could be related to engine, gearbox, final drive, tyres or suspension to name a few without further information narrowing things down.

Hi Liger 1956, just had a whizz up the dual carriageway, does the same when put in 4th at same speeds, but no apparent issues, just the increased humming noise.

That would appear to eliminate the engine and gearbox but not the running gear or final drive. By your location you might be testing it on the Chapel-en-le-frith bypass. If so coming back towards Whalley on the downhill bit if you dip the clutch when the noise is at it's peak does it go away?

I'll give the clutch a dip, on way to work tomorrow and get back to you. Cheers for your help so far.👍

is it worse turning to one side or the other? 

if its constant in all gears, comes in at a speed and then fades at another, its likely resonating. try listening at 30-35mph too...

Also as a wildcard quickie,  worth a check of all 4 tyres for uneven wear, not uncommon for Mk2 Octy's to eat one side of the tyres especially on insides at the back 'saw toothing' etc. 

On 28/03/2021 at 18:15, mac11irl said:

is it worse turning to one side or the other? 

if its constant in all gears, comes in at a speed and then fades at another, its likely resonating. try listening at 30-35mph too...

No issues when turning.

Hi guys, not dipped the clutch as yet, but, I started the car tonight and revved it, and there was a whining noise, a bit like something toothed rubbing against each other. The car was in neutral at all times. 🙄🤔

That changes things if the noise is engine speed related.

When was the cambelt last changed and does the auxiliary drive belt look ro be in good condition and adequately tight?

Was the air conditioning turned on at the time that you heard the noise?

was it definitely the same noise though? a bit odd (to me) that a noise that present in a particular wheel speed range regardless of engine speed (dropping to 4th) is also present revving in neutral?

 

was it a cold start revving or were you up to temp at the time?

 

my senses keep saying check your wheel bearings..

Pardon me if you've already covered this but could there be two sources of noise which are confusing the other?  A failing wheel bearing would produce a running hum or groan which is engine independent and only varies with roadspeed, whereas a worn belt would produce a noise which was engine speed dependent.