A 1987 Chevy Blazer uses R12 refrigerant as shipped from the factory. Most have been converted to the more environmentally friendly R134a.
no such thing
Could be low or over charged with refrigerant.
All vehicles 94 and newer use R-134a refrigerant, 93 and older use R-12. There is a website that has helpfull information about your vehicle ac system www.idqusa.com.
Check the refrigerant level first.
in line with the ac lines there is a little screen filter in the line that filter could e clogged but the ac has to be discharged to find out. also the incorrect pressure of refrigerant can also make the ac not work properly