Noticed today that with the aircon on I can hear slight whining noise (faintly noticeable).

At first I thought it was coming off the radio/stereo (ie alternator/earth whine), but I turned off the stereo and it was still there.

I switched off the A/C and the whining stopped.

You can't hear the whining if you're driving along at say 25mph and over. I'm guessing this is because the diesel engine and road noise is drowning out the whine??

Is this a sign there's something wrong about to happen? The car has a few more weeks of warrenty left with Skoda, so ideally if it is an issue, I guess I'll get it booked in.

What do u guys think?

Did it rain where you are today? (don't worry this is relevant!)

yes rained like a monsoon, and mostly on the motorway too, so i guess the engine bay would have got soaked.

I forgot to mention it rained, thought it might have some relevance funnily enough

So what does the Rain do to make the whining noise?

To be honest I'm not entirely sure! All I know is that mine does it as well, and its always done it when its been raining hard. Once the car has dried out somewhat, it goes away again!

Thanks for the reply,

puts my mind at rest knowing that it happens on another car, atleast I won't need to book it into the dealers now

I'm not completely sure.. but think this is something to do with a wearing bearing,,

FWIW, mine does it when it's due a top-up. Since Hellfrauds have their "if it ain't broke, you don't have to pay" offer, it might be worth getting them to give it the once-over.