Hey all,
I have a 92x with R-12 in it. I want to convert to R-134a via the writeup included on this site. How do I check for leaks? I am pretty sure that my system isnt leaking because when I unscrew the cap (dont know what its called, but its on a hose near the firewall on the pass side of the truck and it looks like the valve on a bike tire where if u push on a metal pin it will open the valve) there is a hissing sound - indicating that the system still has pressure. and since it is a 92, i dont think it would still have any pressure if there was a leak. does this sound right? or should i test it some other way before i start the conversion?

Does your a/c still blow cold air now? If so it probably isnt leaking. You can stick a thermometer in the vent with the a/c on and it should be about 20 degrees colder than the outside air if its working properly.

Checking for leaks is mainly done either by using an electronic sniffer, or putting dye in the refrigerant and using a blacklight after some time of operation (days or weeks). What would be helpful is to know your system operating pressures. If you plan to convert I'd recommend you buy a set of gauges as part of the cost.... you will need conversion fittings for that gauge set.... I'd echo Redrig'scomments, how is the system operating now? If it is cold, have an AC shop check the operating pressures and recover the R-12 then bring it home and convert it, using your new gauge set and a vacuum pump.

push on a metal pin it will open the valve) there is a hissing sound - indicating that the system still has pressure. and since it is a 92, i dont think it would still have any pressure if there was a leak. does this sound right? or should i test it some other way before i start the conversion?

That isn't an accurate way to test for pressure. Anyway, static pressure will be different based on ambient temp.

So the best way to check for leaks is with a "sniffer", blacklight, or put the a/c system under a vac.

If you can't run any tests then yeah, if your a/c is working well then you are prob. ok.

it doesnt work at all. so looks like ill be investing in a dye kit. also, how do you tell if your compressor is still good?

instead of payin $$$ for a dye kit, could i just spray soapy water on all the hoses/fittings then turn the system on, or would a leak be too small to see with this setup?

soapy water will work..or u could buy a jar of the green bubble crap it is a little more sensitive then soapy water