Help! D3 engine started sounding like a lawnmower...

[tickedon]

Or at least that's the best thing I can think to compare it to.

Have a 2013 D3 S60. I noticed about two weeks ago that the engine didn't sound right above 34/35mph and sounds very unhealthy, and the noise progressively gets louder the faster you go. Below 30mph you can't hear anything other than the usual engine sounds. Whereas at 70mph it is at a fairly high pitch, very much like a lawnmower, and as if something is vibrating very fast (at least that's what it sounds like to me). The noise increases the faster I'm going between 35-70. Going uphill the sound seems to disappear, going downhill it seems to get worse.

My car had it's 5th service on Tuesday, dealer took it for a 20 mile test drive and confirmed that the engine was indeed noisy but nothing to worry about ("some of them just are") and also said they'd looked it over and could find nothing wrong. I could accept that if it always sounded that way, but, it was always rather quiet in my opinion and this is a new development.

It is sufficiently loud that I need to have the radio at almost full volume to drown it out... I haven't noticed any loss of power or other issues since the noise, everything seems to be ok, just rather loud and unhealthy sounding.

Have tried searching but without a good way to describe it I've found it difficult - so does anyone have any ideas please?

[craigv60]

Have a look round the engine bay for anything that could be loose or resonating, e.g. the intake snorkel of the airbox, the airbox itself, the big hard plastic hose that goes from the airbox down to the turbo, etc.

On my old Passat PD130 the intake snorkel came slightly loose and made a ridiculously loud vibrating racket. A large blob of Blu-tak sorted it.