Any way to tell if your a/c is running R!2 or 134a?

[DanMcG]

The A/C in my 85 stopped working last year but I never bothered with it since I don't drive it much. Lately I've been thinking that I should charge it up and get it working just because. I do have some R12, but when I pulled the cap off the port it has the quick connect fitting like 134a uses.
Would it be safe to conclude that the system was converted to 134a by a previous owner? and is there anyway of telling whats in the system?

Thanks

 

[yevgenievich]

If it has an adapter then it was converted. But no way to tell without pulling everything apart on what was used and what oil is inside.

 

[DanMcG]

Thanks Viktor, Would you use straight refrigerant or refrigerant with oil? The system has no noticeable leaks..
And if I was to do nothing and waited to next year, is there any chance of doing harm to the system components if it has little to no charge in the system?

 

[yevgenievich]

if it is loosing charge, then there must be a leak somewhere. This also would be a point of moisture entry once pressure is lost. It would be recommended to at least replace the dryer and the orifice tube. Can blow out the system and do a fresh fill of oil and refrigerant at that time. Otherwise just try a regular 134 fill and hope for best. Get a can with a dye in it to help find the leak.
Autozone rents gauges and vacuum pump