Hi!

I have a Stilo MW 2005 1.4 16v with manual air conditioning.

I have a strange noise, something like a metallic hiss, when driving with A/C on and putting load on the engine. It seems it starts and stops with the A/C compressor but it can only be heard when pressing gas pedal. If car is idling or if gas pedal is not pressed it doesn't occur.

Belts have just been changed, A/C has been filled and serviced with no leaks in it, but the noise just stays present, which makes me think it might be the alternator going bad. No other problems at least that I know of.

Anybody have any clue what's going on with my car?

Thank you for your help!

The compressor will normally shut off when accelerating hard, to give all power to the engine, and then kick in again afterwards. Might have something to do with that?

Thanks for your reply.

I don't accelerate that hard, so the compressor is on when the noise happens.