The Air Con in my 2003 E320 will start off blowing cool, but will sometimes begin to blow ambient temp. air...One guy told me it was climate control, but I explained even when I have it on "Auto" full force it will decided at sporadic intervals to stop blowing cold air. The air compressor is also running loud at all times that the AC unit is running.

Please Help me...any advice would be much appreciated. Best, M

Most normal a/c leak 2 oz / yr if the system is in good shape. Yours is an 03 so 9 yrs x 2 oz is 18 oz loss and this will affect cooling assuming you never added freon. You probably just need to top off the freon and don't have a leak.

If you have however had to add freon you may have a leak. IN any case have it checked.