Engine Size: 2.2
Refrigerant Type: R134a
Ambient Temp: 80
Pressure Low: 35
Pressure High: 170
Country of Origin: United States
I recently replaced the compressor, accumulator, and orifice tube on my 99 cavalier due to a leaking compressor. I charged the system using my gauges, but am not sure what readings I should be getting. The Hanes manual I have says the capacity is 1.5 lbs. of freon, but does not tell me what the pressures should be. I added 2 12oz cans and the system seems to working just fine, but I would like to be sure it is properly charged. Can you tell me what the high and low side pressures should be?
If you pulled a vacuum and charged the factory spec 1.5lbs into that vacuum your good to go.
is it cooling fine?
'00 Pontiac Sunfire 2200 I4 SFI
'99 Chevy 4x4 Z-71 5.7 Vortec v8 CPFI
'97 Chevy 4x4 6.5 Turbo Diesel 2500
'95 Pontiac Grand Am GT 3100 v6 SFI
'88 Chevrolet Camaro IROC 5.7 TPI(49,000 original miles)
I typically don't worry about pressures, temps- as long as the right charge is in it, and it cools, (there are many variables, like fan speeds, ambient temp, air flow across condenser, compressor speed, - all that factor in- this has all been optimized in the manufacturer's wind tunnels- why try to better them? - when all you need to know is the refrigerant charge amount which is printed underhood)- then all else falls into place-- Of course I look for exceptions- like high head or low low suction-- but you don't need to tweak anything, if you are confident in your measuring system for charging.
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
I shoot for around 26-27 psi on the low side, monitoring the high side to make sure it's around 250 psi or lower at 85*F, doors, open, engine at 1,500-2,000 rpm, blower at max, adn also good to turn on the AC. Pay for more attention to the inlet and outlet temperatures of the evaporator for equality with a hand feel. Not a good idea to hand feel the high side, that gets kind of hot. Vents temps are also hand felt, but most accurate measurements are made with only one center vent open. Also listen to the sound of the compressor, start over charging and that baby is straining. Most important goal is that the vehicle feels comfortable, don't go nuts with a thermometer sticking in the vents. Like using gauges just to know the high side is not going through the roof indicating problems, or way too low with compressor wear problems like a leaky check valve, like around an 7-8:1 ratio between the high and low side pressures, but this again is at 85*F.
CCOT systems are far more critical in that at high ambients, high side can go through the roof, and low side is so high, not much cooling, but at low ambients, system will cycle like crazy, park the vehicle in the shade and close the doors for the best test. Also keep an eye on how much you put in, never look at just one thing, look at everything, feel, and listen. Experience helps in determining if a system is right on or not. Can also increment the charge while monitoring a single open vent with a thermometer until the vent temps no longer decrease for an optimize charge, but this is for a specific ambient temperature.
Yes I did pull a vacuum before charging the system and the air is colder than it has been in a long while. Thanks for all the help.
24 ounces of refrigerant.
Low: 32 to 65 psi
High: 150 to 324 psi.
As GM Tech has mentioned, it's best to charge by weight and then see how the system performs. Charging by pressures may provide a false picture id something is not working correctly.
We've updated our forums!
Click here to visit the new forum
Copyright © 2016 Arizona Mobile Air Inc.