What type of refrigerant does my AC unit use. Last two times we used it it would ice over and once it thawed it would be fine. A friend of mine says it's probably low on Freon and he was asking me ...
unless your friend is a "full service appliance guy", he isn't likely to be successful regardless of the "freon type"... there are NO service ports to make any "additions".
Although it could be "low", your problem is more likely an issue with air movement. Check to ensure things are clear and fan is operating correctly to ensure proper air flow.