1972 454 convert. What temperature should the air be that is coming out of ac outlet in cockpit. Mine reads 61 degrees. Was just re-charged. Is this normal?

 

It all depends on the outside air. Really good would be about 20 degrees colder.

 

47 to 50 in mine

 

40 degrees F would be optimal.

 

What was the outside temp at the time. Was the car moving with airflow going through the condenser? What rpm was the engine running? Does the heater valve operate properly?

 

there are charts somewhere that calculate
outside air vs duct temp and lowside pressures.

your temp sounds high?

 

I-recharged-mine-yesterday-85-in-my-garge-50-in-my-car-all-orginal

 

Using R12 or 134? Would that make a difference?

 

This is a pretty good guide even without gauges..
38-46f @ clutch cut out…2000 rpm 80f or below outside and LOW fan speed.
i think yours should be similar..
instruction for 79.. r12.
mine cuts out around 43f..

 

I'm getting 40 - 42 with temp probe just inside center vents.
Fairly new Sanden compressor, parallel flow condenser running 134 freon.

 

i put R22 in my truck once long ago. that was cold!

 

But where do you get it Derek?
And I had my vent temps colder still on 134 , but then my evaporator was freezing over. Had to adjust my thermal switch back.

 

Thanks. That really helps give me a perspective on what I should expect.

 

Diagnostics of the A/C system is the only route to success. "Was just re-charged" and it's 61 degrees should be an alarm bell sounding off in your head. How was it recharged...one of those spray cans or was the system evacuated and a full charge to factory spec done? But more importantly, BEFORE "re-charging", was the system checked for leaks? If it was low on refrigerant before the re-charge the system is leaking. There is no such thing as "topping" off an A/C refrigerant system. I'd be a rich man if I got a dollar every time I heard someone selling a car said the A/C works but just needs to be recharged. No, it's broken and needs to be fixed. If real A/C manifold gauges were used for the "re-charge" maybe the pressure was higher but that means little to whether the A/C system is functioning properly. Gauges would show pressure information that helps to determine if the compressor is working properly or not.

Regarding R-12 and R-134, your system was designed for R-12. Hard to get because it's outlawed but it is out there and many owners go with R-12 because the system works best with it.. As for R-134 "conversion", that means more than just shooting new refrigerant into the system. The system needs to be properly evacuated of the old R-12 and the oil. If the system hasn't worked in a while or hasn't been used regularly in a long time I would replace the drier (whatever the desiccant device is called in the 1972 system) and the filter along with all of the O-ring seals plus do a full proper flush (A/C solvent) of the lines, condenser, and evaporator before any oil or refrigerant is put int the system.

Last year I got my 1978 Corvette with a non-working factory original A/C. I diagnosed the problem to be a failed compressor which the previous owner's mechanic had replaced but they didn't replace the orifice tube filter or do any other things to prep the system. So the new compressor was ruined by pre-existing trash in the system. Prior to that I had verified the HVAC vacuum and electrical components were working inside the cabin and engine bay. I solvent flushed the system, replaced the failed compressor (diagnostics!), new accumulator (drier), new orifice tube (filter), seals, new R-134 compatible oil, etc. It held a vacuum overnight so no leaks. I used R-134 instead of R-12.I have driven the car 5,000 in the past year and the A/C is still blowing 45 degrees out of the vents.

Don't throw parts at the A/C system. Have proper diagnostics done on the system to understand what is wrong and why. Then repair it and enjoy the cool air.