Alright so I put a brand new AC compressor and tank in my 97 s10, filled it with new r134 and oil and made sure its at the proper pressure. It gets cool, but not cold, not cold enough for a real hot day, but it is cool. I even added a bit extra refrigerant and upped the pressure just a bit and it didn't change it much. It's held current pressure for a week now. Any ideas?

 

1. "Tank" are you referring to the accumulator?
2. Did you evacuate the system to 29.4" for at least 1 hour before charging?
3. When you added oil, did you flush the entire system first?
4. Where and how much oil did you add?
5. Did you use PAG150 oil?
6. Was the compressor charged with oil when you purchased and installed it?
7. Adding "extra" refrigerant will cause a loss in cooling performance, guaranteed.


Checking pressures, especially high side, vary substantially depending on ambient air temperature, ambient humidity level, cooling system temperature and overall cooling system condition. A "slightly" more accurate way for diagnosing certain AC problems, is to measure clutch on time, off time, total cycle time, and what the pressures are when the compressor comes on, and when it shuts off.

 

1. Yes, the accumulator, my mistake.
2. I did not...
3. Cleaned it out best I could
4. The new compressor was filled already, I put in a can of mixed refrigerant and oil, 3oz?
5.^
6. Yes
7. Did not know that

I have just been running it on AC Max, the compressor is on all the time.

 

#2. When you drained the system, it acquired atmospheric pressure, (roughly 14.7psi). If you add the proper amount of refrigerant, the system is now seriously overcharged. Evacuating does two things: #1 it creates a vacuum in the entire system equal to minus 2 atmospheres, (29.4" Hg). Evacuating assures there is "nothing" in the system. #2 Moisture, in liquid form, can not be evacuated. The vacuum causes any moisture in the system to vaporize, which can be removed by the evacuator. It takes roughly an hour for this to happen, and the longer you leave it on, the better. 2 hours is good insurance


#3. There is no "oil dipstick" on these systems. Too much oil will cause poor cooling performance. Among other things, oil does nothing for cooling, (lubrication only) there is less "room" in the system for the refrigerant. If the compressor sucks in too much oil at one time, it will destroy it, (oil can be pressurized, but it can not be compressed). Too little oil will destroy the compressor from oil starvation. The entire system MUST be flushed using the proper tools, procedures, and solvent. System oil capacity is 8.5 ounces of PAG150 oil. During assembly, the oil must be distributed correctly into the condenser, evaporator, compressor, accumulator, and lines.


#7. These systems are very sensitive to the amount of refrigerant charge. As little as 2 ounces too much or too little will noticeably affect performance. There is no "dipstick" or magic formula for checking pressures and cycle times to determine the amount of refrigerant in the system. The ONLY way to know how much refrigerant is in the system is by draining, evacuating and recharging with the proper amount. When charging, refrigerant in the charge line must be taken into consideration. For example: If the refrigerant cans are 12 ounces each, and the system capacity is 36 ounces, 3 cans is not enough due to the refrigerant left in the charge line.


On your system: without evacuating, and then adding a little extra refrigerant, each one is serious, and you've got a double whammie going on. No wonder it's not cooling sufficiently Basically you need to start from scratch. Drain, flush, add oil, evacuate, & recharge.


A/C is not the addition of cold air, it is the removal of heat. Heat is removed via the condenser. The engines cooling system plays a huge part in the removal of heat, not only from the engine, but the condenser as well. Radiator, thermostat, water pump, hoses, fan clutch, condenser, etc etc, they all need to be functioning as they were designed.

 

Alright, so I evacuate the system by letting it run without refrigerant to it? It will just have oil in the system?

 

You will need to buy or rent a manifold gauge set and an evacuator pump. The evacuator is connected to the system after the oil is installed. Then the vacuum is drawn for a minimum of one hour. The evacuator will not remove the oil, only moisture.

 

I redid my A/C back in late June. Followed Captain Hook's advice to the tee and now my air will freeze me out of the truck (2000 S10 Pickup). Here is all that went back and forth while I was doing it. I was fortunate - my compressor did not fail just had a small leak. If you old compressor failed your system is full of debris your system needs thoroughly flushed and the condenser flushed. Here is a link to my post back then.

https://blazerforum.com/forum/2nd-ge...pressor-90114/