DIY Bone chilling AC

Myself and others on this board have experienced what we could call “less than great” performance from their Cruzens air conditioning system. My AC would do a fair job of keeping the cabin cool at best in hot and humid weather. All of my prior cars have had bone chilling systems when properly set-up, and I frankly needed more from my current system in the cruze.

First there are different approaches toward this project. Some say just go get a liquid refrigerant “charge system” from the parts store, and top off the charge and be done with it. As this is an option it only gives you limited insight into the system, and leaves you guessing at the total charge.
Here is my approach.

Assembly all the tools and supplies needed to get the job done. I perform all my own repair and maintenance work to not only my home, but my vehicles also. I already own a set of compound 134a gauges and hose set. You can pick these up at an auto parts store for approx. $90-$100, and most have had good results with the “Harbor freight special” for approx $50. I procured my set about a year ago from Advanced Auto for a really good deal, so I can’t personally vouch for the cheaper set
.

You may find different opinions in regards to brand and composition of 134a. I personally used “straight” 134a without any additives.

There is a pressure temperature relationship with all refrigerants. It is essential you establish current ambient temperature and humidity levels prior to starting. As you can see I used a multi-meter set to the Temperature setting as degrees. I checked my local weather station app for the current humidity levels.

My readings were 82 degrees with approximately 62% humidity.

I retrieved the necessary charts and information relevant to the job from the service manual.

Note: For my readings the low pressure side range is (30-45 PSI) and the high pressure side range is (187-232 PSI) and vent discharge minimum temp should be 59 degrees (that’s pathetic).

Note: Vehicle should be warmed up to operating temperature, no supplemental fans to move air across the condenser, AC on highest setting, recirculate enabled, and all discharge vents open, with your reading taken from the left center stack. Run AC for 5 minutes with the driver window opened approx 5-8 inches.

Probe placement (left) Actual reading taken prior to charge increase 47 degrees (right)

My goal is increase the 134a charge to within the “upper range” of the specs and lower vent discharge temps.

Pop the hood and locate the low and high pressure service ports (low pressure left) high pressure (right). Both are on the passenger side just behind and below the air box.

Unscrew the plastic caps and put them safely aside.

Fashion the gauge set as pictured. Make a loop with the yellow charge/vac line (2nd from left), and make sure all valves are closed and o-ringed connections tight. (Note: I will be using a small 12oz charge that hooks directly to the gauge cluster((pictured far left). If you own or have access to a larger charge cylinder you may use the yellow charge line directly) The hoses and connections are not only color coded, but labeled, and different sizes so it's almost idiot proof.

Hook up the low and high pressure "quick connects". They operate on the same principles as compressed air fittings, and couplers.

With all connections made and the AC running as described above open low, and high side valves and obtain your reading.

As you see my readings are "within" spec low side 32 and high side 210ish, however not in the upper range.
Note: Also if your gauge set contains a site glass you can view the condition of your refrigerant, dye, and oil. (GM puts puts dye in from the factory)

I added charge to the LOW PRESSURE side only (very important) a little at a time and brought pressures up to approx 42 low side and 235 high side. This favors the higher values within the given specifications.

Results you may ask?

A 12 degree drop in vent discharge temps.
I now can drive around without having to have the AC on full blast and be very cool and comfortable!

Close all valves, and disconnect your fittings, and don't forget to replace the plastic caps back over the service ports.

Keep in mind some mechanical inclination is required to do this, and I in no way will be held responsible for damage or injury. Also note it is federal law that prevents directly venting 134a into the atmosphere. DO NOT vent 134a into the atmosphere!

Thanks and I hope this helps fellow Cruze talkers!