LTCMontana

I have a 95 968. The current compressor has an R-134 designator on it.

I ordered a replacement which says fit a 92-95. However, it is designated an R-12 on the case. Can I use this one by changing out lubrication? Or do I need an R-134 compressor?

chudson

A compressor is nothing but a refrigerant pump, and many R12 have been successfully converted to R134 including one of mine. But if I were replacing the compressor on my '93 I would prefer a unit originally designed for 134.

Was this compressor new? If so I'm curious, from where?

If it is filled with 12 oil, getting it completely flushed (to the point of dry) without disassembly is difficult.

Jay Wellwood

I *think* that the compressor cares not what it is compressing as it is just a gas anyway until the gas passes through the condenser where it becomes a liquid, then passes through the evaporator where is is returned to a gas, removing the latent heat of vaporization - making you happy.

That being said, conversion from R12 to R134 typically requires replacement of the dryer and the o-rings that make up the sealing connections in the system IIRC.

The primary differences in R12 and R134 are 1) R134 is environmentally friendly, 2) R134 is more widely available, and 3) R12 *seems* to have a lower evaporation temperature/heat capacity (based on my calibrated thermal appendages).

djantlive

Once converted to r134, use 80% of the refrigerant so the system works better and lasts longer

griffiths

1995 is a R134a system. Use the amount of refrigerant specified by the factory. (do NOT use 80% of it, use all of it).
Drain all the oil out of the new compressor.
Put in PAG46 oil, about 5 oz should be safe.
Put in a new drier as well.

LTDzak

The coupe I bought earlier this year had an R134a conversion done by a noted midwest Porsche indie. When the compresor is engaged at idle the engine vibrates quite a bit. I wonder if he used the R12 weight when charging.

griffiths

The best test is throw a set of gauges on it and check the low and high side pressures at idle (compressor running) and compare the high to the outside air temp around the car.

Boeing 717

Sorry, quick hijack.
Griffiths, should the compressor come on when you turn the ac switch on even with the fan switch off?

griffiths

Here ya go high jacker, lol
READ

Boeing 717

Thanks.