Freon booster kits?

[mnormand]

Can someone educate me on what this is? I see a big rack of this at AutoZone for cheap. My a/c is working fairly well, but not -quite- as good as it used to. On long trips it seems like its not putting out the colder air it used to. Once in a blue moon the cool air will fade slowly into not so cool.

I'm not about to add this booter until I get some qualified info. A/C shop might be next, but no big hurry.
2004 6cyl 4R SR5

Thx!

 

[eskimochaos]

R-134a

 

[borgzman]

There's a thread here, it did mention about a sight glass.

Anyway, those refrigerant kits like R-134a have instructions.

I think we need to locate the Low Pressure Line of the A/C sytem(usually cap is labeled L), and in there we fill the refrigerant while observing the pressure gauge, until the needle in the meter points to the recommended value.
Q:
1. Do we need to evacuate the existing refrigerant(freon)?
2. What is the recomended pressure in the 4Runner's a/c sytem.
thanks..

(I'll do this first in my Tucson LOL!, I'll buy a refrigerant from walmart ha! ha!)

 

[fourwd1]

You don't have to evac the system to add some if you're low.

Low side press - .15-.25 MPa
High side press - 1.4-1.6 MPa