409 refridgerant put in a stock R-12 system works great it blows cold.....I'm talking ice cube cold. Does anyone know the legality of 409 in mobile systems? graemlins/thumbsup.gif

If you mean "409A" aka "FX-56"... it is considered epa acceptable... http://www.epa.gov/Ozone/snap/refrigerants/refblend.html
...5th one down on the list, I believe.

One downside to refrigerant blends or "zeotropic" mixtures (any 400 series refrigerant), is that the composition may be subject to change as the system leaks down. Just the same way you distill alcohol from water, over time, you will loose the more volitile refrigerant in the mix. So if the system needs a re-charge, you would ideally evacuate it under vacuum, and completely re-charge as opposed to just "topping off". If the system is tight, this may not be a big deal, but if recharge is a seasonal thing, it may become a yearly headache.

Good Luck,