I found a tag on the passenger side of the engine compartment kind of by the radiator that is red and says it has R-12. But, I look at the high and low side valves, and they are completely different than my american vehicles. Do they take special tools to access the ports, or has the car maybe been changed to R-134? I do not find any changeover tags anywhere if in fact it has been changed over. I used to do refrigeration, and have some r-12 left over and I also have normal shraeder type valve guages. The compressor runs, but no cool. I wanted to check the pressure in it. Any advice?