Same question, how much should it hold, I had a slow leak, fixed it, now I want to blow out/drain the system and put some new 134 in. I think it would cool better if I got some of the extra oils and stuff out.

 

What year is your car? There is a sticker under the hood that has all of that information on it. Also, it's almost impossible to overfill the system with those cans. You can also check your owners manual.
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Its a 98, great car, their is only a diagram under the hood, no spec's. You are right I cannot overfill it.

 

OOPS! I missed the sticker with the capacity. I looked at the hood and its on the wheel-well, I drained a some oil out and it gets colder now, the drivers side condenser line held a good amount of oil, I will do it again in about a week, after some more oil accumulates there.

 

Glad that's working out for you. How do you drain oil out?

 

The drivers side condenser line by the radiator, it comes right from the pump, it held "some" oil, the system only holds 2 cans of 134, so every bit helps. I had put 6-7 cans of stop leak 134 with oil in it over the coarse of 3 years (very slow leak) It quit leaking, n so now I drain the oil. I have been waiting for the pump to go out so I can change everything out, but it keeps working.
I did a changeover in a 89 Chevy truck to 134, and the trick to get it cooler was to put less oil in so as to make room for more 134, which has (I'm told) bigger molecules than the old Freon.