I seem to remember that my 300SD takes 48 ounces of R12 if completely empty. And assumes that the oil is still inside.

Does that sound right?

What vehicle are you working on that requires that range of refrigerant?

NEVER vent R-12!!!

Weighing the can during charging would be the best way... Stop charging when you have removed the correct amount into the system.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

2001 Honda Civic EX. It says 17.4 oz minimum and 19.4 oz maximum. kinda hard to weigh my 20 oz can because the hose attached to it. I have already done the job. I left about an ounce in the can. A/C seems to be working perfect and my next step is to change the cabin filters.

I seemed to have another problem when I vacuumed the system it seemed like the oil came out. Is this something I need to be concerned about?