Hissing noise from aircon - should I brace!

[drainaudio]

Hi all,
I have a 1993 190E that has factory air con, it was re-gassed and leak tested just before I purchased earlier this year.
Air con has been working fine, very efficient and cold, however today when I turned it on I started getting a loud hissing noise through the dash vents. This seemed to ease off after a few minutes and the air con is still working but not as cold as it was - hissing comes and goes so I've decided to leave off until I can get it looked at. Should I be fearing the absolute worst here?
Thanks Geoff.

 

[joe bloggs]

May just be the gas entering the evaporator via the injector valve you are hearing. If it was a leak that you can hear this will quickly show up when the gas has escaped and the compressor refuses to work due to the low gas pressure releasing the compressor cut out switch. You will know soon enough if this is the case.