MAGK944

Fitting a new compressor and converting to 134a at the same time. Flushed, fitted new seals, new R-D, expansion valve and added 6oz of Polyolester Auto 100 lubricant.

How much 134a do I need to charge? Remember reading somewhere that it's not the same quantity as before the conversion.

Van

Well, before the conversion, it would have been R12. R134a has a different efficiency and different properties. I bet there's a conversion calculator out there.

But, my hunch would be about 2 lbs. Also, make sure you draw a vacuum first.

Tedro951

Some AC mfrs say 80% of the R12 amount. Some say 90%. I did 90.

John_AZ

Not sure of your car.

Late info (convert to OZ)
http://www.the944.com/ac/page05.jpg

Early info
http://www.the944.com/ac/page04.jpg

MAGK944

Thanks. It's a late car so from my calcs it's:

Oil: 120ml = 4oz
Refrigerant: 860g = 30oz

John_AZ

Right

Usually 6oz Polyolester Auto 100 lubricant is mentioned since you are replacing
the compressor, expansion valve and the RD.

Suggested methods;
3-4 OZ in new compressor.
Compressor may have been shipped with PAG so dump out-turn pully a couple of times and refill with POE.

1 OZ in the condenser. Condenser should be flushed when you replace the compressor.

1 OZ in the line to the evaporator & expansion valve.

GL
John

MAGK944

Yes that's what I did except I didn't measure out the oil. Put most of the 6oz in the compressor and the rest everywhere else. It's all sealed up and ready for a charge tonight. Thank you for the help

griffiths

Start with 80% of the OEM R12 charge amount, and then adjust the charge based on a P&T chart.