C204 air con hissing sound

[gnoekuf]

Hi, 

any one have any idea what's causing the hissing/scratching sound from the a/c . Goes off immediately when I turn off the a/c , comes again when I turn on the a/c

[giggss]

happened to me 2 years back..

brought to C&C at Eunos, they can't hear it.
brought to Pandan, finally a friendly advisor say he heard it! But need to leave the car there for them to explore and maybe need to open dashboard and all which takes minimum 2-3 days..

which I did not agree to... randomly went to do a full flushing with 9 degree and the sound went away .. by the way, gas levels are at correct level when checked by outside workshop and C&C.

 

for mine, the hissing sound is very very fine and hard to catch, not everyone can hear it..