Well first of all you have the "parts" of the system listed backwards to what is high or low in pressures.

The pressures are relevant only when the system is operating...When the compressor is pumping gas to the high side to squeeze the heat out of the gas that was absorbed from the evaporator, which is in the cabin of the car. Compressed "liquid" refrigerant "evaporates" into just a gas there!

When the compressor is off, the refrigerant will be metered towards the evaporator, until the pressures equalize.

Depending on the ambient temperature surrounding the stopped system will depend upon the type of refrigerant gas used in the system.


A cars system is about the pressure of a large truck tire (90 to 125 psi) but it's not just pressure you have to worry about! It whether or not you have liquid refrigerant contained and where or what it's going to squirt onto.

You will be lucky, for lack of some other word, if you stuck a knife into a hose of a car because it is using a rubber hose. This means it is using a lower pressure gas that some other refrigerants used in all metal plumbed systems.
The liquid quickly changes from a liquid to a gas and it absorbs heat and if its on your skin or eyeballs they quickly freeze. You can end up with blindness or at least frost bite of skin tissue!
Also there is oil within the gas and you could end up with a real mess sprayed all over the place.

My advise is to forget the knife!
Learn to recover the refrigerant by using the fittings provided.
If you are desperate or are as lame as some lazy mechanics and you can do what they do and create an "oops" leak.
Loosen a fitting and then claim there was a loose fitting found that may have happen in the crash to begin with!
If any one part of the system is open the gas is probably all gone anyway except for a residual bit left in the oil that's in the compressor body itself.


Phil