Automotive Air Conditioning Information Forum

2009 Jeep Liberty KK with 3.7l Engine
My story, sorry it's kind of long:

I had a compressor go bad on me a few months back, so I've been living with no Air Conditioning until I got the money to replace it. Out of an OVER abundance of caution, I replaced everything! The evap core, all three hoses, compressor, expansion valve, and condenser with drier.

When I got the new compressor I drained out the factory oil that it came with. It said it came with 4.4 oz. I for sure got 3oz out into a cup, and probably spilled another oz on the ground. I then carefully added new oil mixed with dye. About 3 oz to the compressor and 2 oz to the evap core. ( The new compressor instruction said to add half to the compressor and half to the rest of the system)

I carefully vacuumed down the system and it held at -29 psi for over 12 hours (got distracted by dad duties). Then attached the Freon (yes it was "Freon" brand R-134a) to the system. I purged the line, and then opened the low side and let the can fill the system with the engine off until it equalized. Then started the car and added the rest of that can, and 6 oz from the next can. That should be 18oz total, which is what the system sticker in the engine bay says it needs.

So here's my problem. With the ambient air temp at 83 degrees F, air conditioner on, fan on high, recirculation on. The air in the center vent only measures about 53-55 degrees F. According to the shop manual, it should be around 45 degrees at that ambient temperature.

Since there was some Freon left in one can, I added that as well. Now the system has about 20 - 22 oz in it, and still has the same

With the engine running, idling, and fully up to temperature, the pressure on the low side reads 30.5 PSI. The high side reads 170psi. These seem low. If I'm reading the Factory Repair and Service manual correctly, the pressures should be 27 - 37 PSI on the Low side and 225 - 325 PSI on the high side. So it seems a little low, right?

Not sure what to do here. From everything I've read it seems the most likely thing I did was add too much oil. I'm not sure what to do from here. Try adding more Freon? How much damage can overcharging the system cause? If I take it to a shop to evacuate and recharge the system will that remove the oil I put in? Kind of a moot point though as shops want $200 - $260 for the service and I don't have that cash right now.

Any input or suggestions would be GREATLY appreciated!

Oh, and I forgot to mention that with the engine off and cool, the pressure in the system is equalized on both sides, and is about the same as the ambient temperature.
Thanks!

Open both front doors, set the cabin fan on the highest speed, and run the engine at 1500 to 1800 rpm for at least 90 seconds to stabilize the pressures and vent temperature.

Record the high and low side pressures and vent temprature while the engine is still running at 1500 to 1800 rpm.

Just went out and did the test:

Engine warmed up fully. Ambient air temp 81% Humidity 51% - Sun is down:

After holding at 18-1900RPM for 90 Seconds--> Low side = 25psi High Side = 225psi and Vent Temp is 57.5 - 58 Deg F.

Immediately after that test, at idle--> Low Side 32psi | High Side 180psi and Vent temp is 60.5 Deg F

Does that help?

Looks like the system is not overcharged on oil or refrigerant.

It does not seem to be rejecting heat very well. You say the condenser was replaced. Are all of the fan shrouds in place? Is the fan working properly?

A high side ratio of 2.77 And poor cooling with 22psi on the low side usually point to poor condenser performance.

Yes, new condenser. On my vehicle it sits in front of the radiator. There is only one fan on the vehicle. It is electric, and is working with shrouds in place. Would it tell me anything helpful if I sprayed the condenser with the garden hose while the system is running to cool it down extra?

Misting the condenser with water is one of the diagnostic tools. Again best done with the full load on the system.

Another test is increasing the airflow. How does it cool at highway speeds? Put you vent temp thermometer in and go for a drive above 50 mph

Yes, I drove it on the highway for about 10 minutes at 65mph. Didn't seem to make any difference. Same vent temp at speed, idle, or revs.

Time for a water test on the condenser then.

Tried the water on the condenser. No real improvement. I also bled a bit out and if anything the vent temp went up a couple of degrees. Today, with ambient air at around 85, with the car running the low pressure is 35 and the high is 175. Seems like the low is a little high, and the high is a little low. Though I do notice that occasionally the fan will turn off, compressor is still running, high pressure will climb to 200, and then the fan kicks back on.

I don't know, I'm about to give up and take it to a shop. Just wish I could figure this out. But it might be time to do a full system recover and recharge. I found a shop that will do it for $145. So that's not hateful. I really just hate admitting defeat I guess.

Alldata states for 1.2lbs of refrigerant.

No pressures were given.