I have a 2010 Mazda 6, 1.8 wagon (several months old and about 5000km). It has been recently making a strange noise when I start it. It appears after a few seconds or so, and seems to be louder when outside is very warm. Sounds like metal on metal or so. Sound doesn't occur always and when appears once in the morning doesn't appear again latter or if it occurs than is much quieter. I think also that only occur when AC is on at the same time when AC starts. Please help, I already visited workshop and there everything was ok (no strange sound ).
Please see the movie under this link
YouTube - ‪Strange sound after startup!!!‬‏

Best wishes

 

Problem fixed!

Broken AC compressor, around 1200E (under warranty).

Best