My dodge durango was not cooling so great so i bought a can of freeon with the hose attached and i read the instructions and plugged it up and it emptied the can in about 30 -40 secs the can said it should take 5- 15 mins...i dont know much about charging the air this was my first time...is this normal?

 

What is the low side reading of the guage, do you have front and rear AC or just front? Is your compressor cycling on and off frequently?