Whenever I start my car I hear a groaning/croaking noise from under the dash.

I finally narrowed it down to the exhaust vent of the aircon. Each time i put the ignition on the vent opens by default and the sound comes. Then as soon as i start the aircon I close the vent and the noise comes again. How can I solve this?.

And is there a way to keep the vent closed by default? It's a pain to keep pressing the close button each time one sits in the car. Plus in winters I don't use the aircon at all, so to close the vent first I have to start the aircon, close the vent and then shut of the A/C.

are you sure that your air con hasn't lost any of it's gas??

Where abouts is the exhaust vent for the aircon? I recognise the noise you describe but I'm a tad confused about what you are opening and closing . It doesnt take much

The exhaust vent i refer to is the outside air circulation system. It's what opens or closes when you press the button to only cirulate the inside air or to get outside air in the car. It's the button below the button for demisting the windscreen.

And the A/C is perfect in Delhi's heat too. So no gas lost.

I hear the noise only when i close the vent or open it. Seems like something somewhere needs oiling. But I don't know what or where...

Yes, been out and done a bit of fiddling with the recirc and I get the exact same noise. Not sure if it is an issue or whether its just the noise it makes?!