How much should a system that is believed to be empty hold? I have owned my X since new. It has never been filled in six years. The AC was not cooling very well last year. This season the compressor would not even come on. I have put 2.5 12oz cans into the system. It seems to be working properly now. Have I put enough, to much, or is it going to explode?

Thanks

I have a 91 Mazda Navajo, so I can't tell you the amount. However if you look at the EPA sticker next to your hood latch you can read the fine print. Mine tells me the Freon load, along with recommended spark plugs, vacuum lines, etc.
The immediate problems due to too much Freon is loss in efficiency. Extreme cases cause damage to the compressor.