The plastic cap needs to be on to stop that small leak when you take the charge hose off, AFAIK that's normal. I think you need to find out where the refrigerant went the 1st time you re-charged it, because that's probably where it leaked this time. Also you need to monitor the hi & lo pressures when you're charging.

 

if it were me I would not use a stop leak because it is a temp fix (if at all) - overall I think if you fix something do it right and do it once (and take your time)

so...i've fixed my high side port before and used the PAG oil to lube the oring - other guys like to use stuff called nylog (thread/gasket sealant)

the low side will be either a schrader valve or port fitting (i'm pretty sure it will be a port fitting) - they are commonly available at autoparts stores

ck out pics of both below - good luck

ps. if you haven't done a leak check on your system - i would check either monitor vacuum or pressure test. if you skip this then at least use UV additive in refrigerant so you can trace the prob. (or perhaps if you still have charge add UV now and leak check)

 

^ Thanks for the pics, that helps.

 

On mine, it was the port fitting. It had a rubbery ball valve that degraded and quit sealing. The cap would slow the leak, but every Spring the system would be empty.

 

I think that's what I've got going on....Except I think my truck has the newer schrader style valve. I believe the ball valve thing is the older version?

 

When I completely changed out my ac (done quite a few trucks as well) I found that valve to be a tad sticky.

Get some needle nose pliers and gently pull on the pin on the valve. Should help close it as that is what I have to do.

Every time I service an a/c system I always leak test those ports with soapy water then dry them off.

That rubbery ball valve is on the high side.

 

^good call. I'll try that.

 

For anyone who my by reading this. I recharged my system and I followed Bean's advice and pulled on the pin a little bit with some needle nose, and the leak stopped! I double checked it with soapy water and it's holding tight.

 

Glad to hear that worked

its stupid i know, but sometimes you gotta manipulate the valve, then check for leaks. high test port especially.