I'm not sure, but I doubt you can charge it yourself unless you have a can of R12 squirreled away and the fittings for an R12 system. Your 1990 was made before the big switch to R134a so unless the system was converted to R134a you will have to take it to a professional.
Even if it has been converted you should take it to a professional. R134a can't be charged by gauge except under extraordinary conditions (see the first source) and overcharging carries a serious risk of ruining the compressor. If you ruin the compressor you would consider the approximately $100 for a professional service to be a bargain.
www.autoacforum.com
Where is the low pressure port for charging a/c in 1990 toyota cressida?
Linear Mode
