I have a very unnerving noise coming from the engine. Easiest way to describe it is that it sounds like the A/C compressor issue when the gas gets low. So like a whining/rumbly noise that you can hear most when accelerating and then coming to a stop and the engine idling. Imagine a noisy bearing on say the alternator that increases in pitch/whine when the engine speed increases.
However the noise happens when the A/C is turned off and only seems to do it on the first journey of the day after the car has sat overnight. It’s done it a few times now. It did it yesterday morning and then when I drove home from work 8hrs later it wasn’t there.
It did it again this morning too.
On a side note I must have a leak on the A/C system as the noisy A/C compressor has returned after a couple of months of the re-gas that ‘solved’ it.

Anyone have any ideas? It’s going in for a 6yr service at RCV on Friday and I’d like to be able to have a better idea on the issue before it goes in.

Ta
Aaron

Also, dont know if this is connected but I had the windscreen changed a few months ago and now the plastic scuttle that slides on to the bottom of the windscreen appears to have dropped leaving a gap in places of several mm between the screen and scuttle.

So I think my problem is the A/C compressor kicking in even though the Econ button is pressed. Last couple of days it's just been randomly making the noise and I've noticed the air comes out of the vents cooler with the faint smell of aircon being turned on.

So... Anyone have any clues as to how or why my A/C is randomly doing its own thing? I know I need to trace the fault as to why it's losing gas and making the compressor noisy.. But maybe someone can assist with the electrical gremlins...

It's pretty difficult to diagnose a sound from the distance or from behind a keyboard.
But, judging from the fact that the noise appears only when the AC is turned off, so when there is much less load on the accessories belt, it could be the bearing from the automatic tensioner or the idler pulley.

Alex, thanks for the reply on here and via pm.
Although the A/C is turned off... At a random time during a journey, the noise just starts and the air coming out of the vents gets noticeably cooler, with a smell like that of the A/C coming on.
As though someone has turned the A/C on.
Sometimes pressing the Econ/A/C button so the whole system is off stops the noise, other times it doesn't.
It doesn't always happen and there is no set time/distance in to a journey when it occurs... Hence the thought that it's something electrical at fault?

It seems that there are two problems. One with the noise and one with the AC.
The noise is made by something mechanical, that's for sure. You should see which part is making the noise.
As for the AC turning on when it shouldn't, I don't know what to say... The AC compressor is driven directly by the engine ECU. I don't see why the engine ECU to turn on the compressor without reason...

Whahoo
Did you ever find the cause of your noise?
I have a similar problem, it is a whirring noise, like a loud fan, that increases and decreases with the engine revs when AC is on, but stops immediately it is switched off.
Garage not sure exactly which pulley - AC, Alternator, Water Pump, Pre tensioner etc as it would appear that activating the AC is putting more load on the drive belt and therefore the other pulleys. Tattoos - Why would you choose to look like the wall of a public toilet?

It turned out to be a tiny leak on the condenser causing the pressure to drop in the system after a few weeks. As the pressure dropped the compressor made the noise. With a full regas and a new condenser it was sorted.

Thank you for the reply. I will pass on the information.

The garage are looking for a bypass belt that will enable them to isolate certain pulleys in order to establish which is the culprit. Tattoos - Why would you choose to look like the wall of a public toilet?