recharging the a/c: how much?

[yellowstang1994]

I checked the freon in my car today because the the a/c is blowing basically whats outside, the gauge says i'm fresh out. I understand everything I have to do but i'm not sure how to check how much I need to put in. I guess I could take it off a bunch of times and test it with the gauge until it reads 'full' but that sounds like a pain. Do I just fill it up and test with a thermometer in the interior vent until it's 30-40 degrees colder then the ambient temp. outside? I just worry about overfilling it or not filling it up with the correct pressure. And do I need any special kind of thermometer for the vents? How do you guys do it?

 

[gcomfx.com]

First you should find your leak.

 

[drakesdad]

I just bought a couple of cans of the blue and white label and the guage stated that it was in the green and it was still blowing warm air on our GTP so we put on another can and all is well at this time.......the blue and white can has some type of leak repair in it.....

 

[HISSIN50]

Do you have manifold gauges?

The first thing I would do is hook up your vaccum pump and try to put a vac on the system - this will tell you how fast you're leaking. It should hold a vac for a min of 30 mins.

Good luck.

 

[99FiveOh]

Three cans is about right. On a manifold guage you usually want to see the low side pressure a little under half of the ambient temp. So if it's 90* outside, you'll want about 35-40 PSI. In all the Mustang's I've recharged, it's taken 3 cans to get the proper pressure.