I used a soup bubbles but couldn't find a leak maybe its a small one.but i can see a little oil drops on the High pressure pipe surface.

Some others keep saying its an expansion valve

Yea checked the pipes couldn't see any leaking .but what is causing Refrigerant to be low?

Updated:
at 2000rpm H was about 125psi
The L was 20 psi

Well i took this pic a while back ago but not 2000 rpm
But yesterday i checked the low pressure at about 2000 to 3000 rpm the low side was 35psi

Hello guys whats up.i have kia cadenza 2011 V6 3.5L. Before a couple year ago I have noticed my car's A/C is not getting cold when it is idling and it make a little hissing noise this only happens sometimes when on a traffic so I have taken it to a repair and have checked the high pressure pipe was ...