A/C freon

[jon0108]

I just changed the evaporator and recharged my system with Autofrost(r-12 substitute). I used 2.25 lbs. as stated on the blower motor cover, but the repair manual says 2.75 lbs. Which one is it?
I am getting a 40 degree reading out of the vent. Is this acceptable?

 

[Z06Marty]

I just got an R-12 freon replacement for an application at work and the instructions say to use 80 percent of the full charge by weight. Marty

 

[jsinga]

Look for a specific charge proceedure for AutoFrost. A lot of the R-12 replacements don't take the same amount to charge a system. It's best to do it by pressure.
What are your gauges reading? What's the outside temp? what is the engine rpm? All of those will have an effect.
40 sounds a little high. But at idle it's not bad.
Run the engine up to 2000rpm. Does the compressor cycle off? If it does you are low on charge. If the pressure doesn't get down to below 35psi you might be over charged.

JS