I just added a can of 134A to my system today. After I took off the quick connector from the charging kit, the low side port started slowly hissing. Refrigerant gas was leaking from this port. Could this be my leak to the system? I quickly grabbed the cap to tighten back on the low side port. Not even sure if this cap was designed to handle the small amount of pressure or if its just a dust cap. Any one had a similar experience or know if this is a genuine leak?

 

I think I just need to tighten the schrader value inside the low pressure port to stop this slow leak.

 

Did that fix your problem? I am having the same issue.

 

i have found that after about 7 yrs or so, its best to just go ahead and replace the valve...then vacuum it down, and refill.

 

+1, the black plastic cap does nothing more than keep debris out of the valve.

 

I might just replace the valve now. System still leaks. Not sure if its from this port but changing the valve can help out.