Help with AC Diagnosis

[Kanding]

Hi guys,

I have a 93 Prizm. The AC doesn't cool as well as it did last year, but the compressor engages and some cool air is still produced. The site glass looks like smoke when the AC is running. With the AC on, I measured about 25 psi on the low side and about 110 psi on the high side. With the AC off, the pressures are about 80 psi low and 110 psi (no change) on the high side. My first thought was refrigerant but someone told me it could be a bad compressor?

I read that the correct pressures should be around 30-35 psi low and 250-300 psi high with AC on, though I am not confident in the source.

Any thoughts?

Thanks.

[kickfli12]

hey, as long as your A/C compressor vacuums down to 30 (and holds a vacuum) its fine. if i were you i would do an R-134A conversion, it costs like 15 bucks for the fittings at napa. R-134A doesn't have the cooling power that R-12 does but it still does the job, its also cheaper. put a thermometer in your A/C vent and check the temperature coming out. the A/C blowing from the vents should be between 35 and 45 degrees at the lowest setting, as long as youre in between those numbers you shouldnt mess with it. i did this to my 93 prizm. if you need part numbers for the fittings let me know. i hope this helps.

[Steelballz]

i'm not sure on AC pressures, but if it looks like smoke on the glass then I'd get it re-filled and see how that changes the situation

[Monkey123]

I sorry for cutting in like this instead of create a new thread. I want to do a conversion from R12 to R134A on my Corolla 1993. Do I have to vacuum out moisture and old refrigerant (R12) from the a/c lines? Would R134A freon creates leaks in the near future for a R12 a/c lines? Thanks for all the advices!

[Kanding]

Thanks for the input guys, I appreciate it.

[kickfli12]

Originally Posted by Monkey123

I sorry for cutting in like this instead of create a new thread. I want to do a conversion from R12 to R134A on my Corolla 1993. Do I have to vacuum out moisture and old refrigerant (R12) from the a/c lines? Would R134A freon creates leaks in the near future for a R12 a/c lines? Thanks for all the advices!

you will need to buy fittings like i told the first guy. they only cost like 15 bucks at napa. yes you need a recovery machine to recover the old R-12 and oil. no it wont do any damage to your existing A/C system. the fittings are the only parts you need. any shop that offers A/C servicing can do this for you. hope that helps.