Does my car take R12 or R134a coolant? How would I know?

I checked the port, and I do not know what the normal or small size would look like? I will tell you that I am the only owner of this 1991, I bought it cash back in 1991. I don't think there was any conversion. I bought the car in California on December 28th 1990. So am I safe to say that since it is probably a R12, I cannot use the R134a? will the gauge-tip not fit or? I am totally ignorant about this part of the car.

NO,the R134A quick connect fitting WILL NOT fit on your R12 port.if you just need a charge,if you can find a local trusted a/c shop,they make a FREEZE 12 freon.i had some put in my 91 accord EX about 10 years ago,and the guy charged me $30.00?but that was 10 years ago.you can also buy the R134a change over kit at most autoparts houses,and maybe wal-mart.i have a 93 accord now that has R12 in it still.i get the best cold air by pushing the button to the right,not the button for pulling in outside air.

THANK YOU FOR YOUR RESPONSE. IS IT EASY TO SWITCH FROM r12 TO R134A?

yes it's easy.just follow the directions on the kit.one of the kits they sell is made by Quest,complete kit. QUEST R-134a AC RETROFIT & REHCARGE KIT -- 3 cans refrigerant, oil, hose & fitting's,part number (321).i saw a few on e-bay.one is $45.00 plus $10.10 shipping.i'm sure they are more than that at a parts house.good luck with it. Quest R-134a air conditioning retrofit & recharge kit, converts R-12 refrigerant to the new R134a, complete kit includes ( 3 ) 12oz. cans of R-134, oil with additives, recharge hose, hi and low fittings.eBay item number:231515868805

I have never changed such a part. Is there just one hose to change or what? Maybe you can give me a quick idea on how to replace this if you have the time? It would be so appreciated!! Jim

you don't have to change any hoses.you just screw the 134 fittings down on to your r12 fittings on your car,and that's it.once you do that then the new 134 fittings are quick connect fittings,then you just use a 134 hose on the low side to put the freon into.like i said the conversion kit comes with everything you need.some people will vacuum the old system out,and some will not,just depends on who you talk to.i have seen people change these over and not vacuum them down and they work better than the r12 did.