Yeah, both are required! :p I feel you on the heat. My trucks A/C didnt work so I pulled a vacuum for 30 minutes on it and filled it with 55 psi of liquid propane. seems to have a slow leak somewhere (found some bubbles on high side fill post) and R134 is ~$30 a lb out here. So far so good, cools enough to not have to use 4th fan speed. Propane is also called R290 with no stink in it, used in reefers and RV fridges.