Refrigerant - how do I know if the conversion has been done?

[Pauwl]

How do I know if the conversion from R12 has been done?

Last time my system was filled, it was empty a few days later.
The radiator looked terrible, so got a new one to put in.

Before I fill it up again (and it's the seals elsewhere), how can I check if the conversion has been done or not? I presume without conversion it would just leak out again?

any ideas?

thanks,

[s928s]

CHECK THE SERVICE VALVES, THE R-134a VALVES ARE LARGER AND COLOR CODED WITH RED AND BLUE CAPS. ALSO THEY USE A QUICK RELEASE CLAMP FOR THE SERVICE PORTS. THE R-12 USALLY WITH PORSCHE HAS BLACK CAPS AND THE SERVICE VALVES LOOK LIKE A LARGER TIRE VALVE, THREADED ON THE OUTSIDE.

[Thunder]

If it was me, I would let the 928 sit at ambient air temp ensuring the refrigerant system is at ambient air temp, then measure the ambient temp and record that temp. Now I would hook up a set of guages to the refrigerant system, take the pressure reading, look up on a pressure temperature chart the pressure and temp (The ambient temp at the time I took the pressure reading, and the pressure reading of the system). Thus the pressure with the correlating temperature will let you know what refrigerant is in the system. This is true, if there are no non-condesables in the system or has a mixture of different refrigerants from the previous mechanic (if thats what they can be called in some instances).

Fittings can be found to put R12 in a R-134A system and vice versus without changing any fittings.

The best way to check is by taking a sample of the refrigerant and it be analyszed under a spectrometer, the second best method is by the method I have mentioned.

[Pauwl]

My system is totally void of any refrigerant at the moment, so unfortunately no checking ambient temperatures.

DAVID, where can I find the service valves to check the colour?