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DIY Bone chilling AC

48868 Views 25 Replies 10 Participants Last post by  blsnelling
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
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You may find different opinions in regards to brand and composition of 134a. I personally used “straight” 134a without any additives.
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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.
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My readings were 82 degrees with approximately 62% humidity.

I retrieved the necessary charts and information relevant to the job from the service manual.
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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)
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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.
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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.
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Hook up the low and high pressure "quick connects". They operate on the same principles as compressed air fittings, and couplers.
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With all connections made and the AC running as described above open low, and high side valves and obtain your reading.
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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?
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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!


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Also realize this will only help if your system is mechanically sound, and free of leaks.
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Nice write up. This is the correct way of achieving proper performance from your a/c. Same way to do it on your home a/c too.
Finally found this. I'm about to check mine because the ac is just not cool enough after 4 yrs now of service

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Cruze uses the V-5 variable displacement compressor, rather similar to the old POA systems used in the early 60's. The easiest way to proper charge these systems is to use a GM charging station, You connect the low and high hoses to the system, draw a vacuum to the connecting hose than recover all the refrigerant into a calibrated tank. Correct charge is 1.38 pounds of R-134a, so you either add or subtract from it to get this to the correct amount then put it back in.

So you don't have a GM charging system, so what do you do next. Charging by pressures is only good in a CCOT system, very misleading with a variable displacement such as the V-5, pressure are all over the place.

The ideal method of charging, first all, this must be done above an 85*F ambient, and your goal is to charge just enough to get solid liquid in the high side line. Then can add an extra two ounces for the accumulator. Do do this accurately, should have a sight gauge. But with a very fine feel, you can feel pulsations in the high side line when low, just add charge to the low side and don't forget to purge the lines first, until these pulsations cease. But this takes experience.

Undercharging can restrict refrigerant flow where you won't get proper lubrication and will burn up your compressor. Over charging, you may blow your system if the high thermistor isn't working properly, or otherwise will get a high cycling rate. The V-5 does not cycle, runs constantly when the AC is on.

You are correct about staying away from additives, can ruin a perfectly good system.

Also the V-5 is designed for fuel economy, the cooler it gets, the less pumping it does, the hotter it gets, this is when your vent temperatures should really drop.

Then the R-134a ports are crap, uses a large neoprene disk that can slide horizontally but will have a bead in it. If this doesn't seat exactly, will end up with leaks. This was done by that AH, Al Gore when he took over the EPA in 1993, also pushed R-134a because DuPont just got a patent on it. Suppose to save the world, but now contributed to global warming.

Also uses PAG that is like a women's facial cream, get any moisture in these systems, forms an acid, then you really have problems. But the cure is simple, just replace the entire system.

Unless you have years of experience, strongly suggest you don't touch it.
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Well I done this today and got very close to the top of the ranges and wow very very cold air now! Thanx for the write up!

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Well I done this today and got very close to the top of the ranges and wow very very cold air now! Thanx for the write up!

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At what ambient? Let us know how it works if the ambient increases. Ambient temperature variations for AC is in the range of 38*F up to 135*F, and yes, can be optimized for any particular temperature. But what about the rest?
awesome write up, chalk this up as the next project before the summer humidity kicks in full swing.
Nick d 81 degrees and 46% humidity. I worked at a a/c shop for quite a few yrs before I decided to work on bikes. The OP write up is perfectly find if u monitor both high and low side pressures and don't go over maximum operating pressures.

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I figured I better show my results for ya'll ? 4 on the fan is too cold!
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I guess I am the lucky one. My cruze has had the best a/c of all the cars I have owned. My corolla had a good a/c and is a close second to the cruze but my wife and daughter are always telling me to turn it down or closing their vents. Luckily I have never had to have service in the four years I have owned. Knock on wood.
Do you feel your Bone Chilling A/C would chill my Bone as well? 125 degrees coming up in a few weeks. Funny thing though, the CRUZE did great last Summer as the A/C works cool!:eek:ccasion14:
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R134a will evaporate and make its way past the orings eventually, so recharging is a part of maintenance in my book.. Thanx OP for my bone chilling ac!

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^would that not freeze up the evaporator core?
^would that not freeze up the evaporator core?
That's what I was thinking but hasn't and It's my DD.

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I guess I am the lucky one. My cruze has had the best a/c of all the cars I have owned. My corolla had a good a/c and is a close second to the cruze but my wife and daughter are always telling me to turn it down or closing their vents. Luckily I have never had to have service in the four years I have owned. Knock on wood.
I'd be the first to complain, no complaints! Plus any A/C modifications void your warranty
Lol what ac mod??

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Oh well just in case. I was scared at Poodok's warning and my A/C is strong, not Bone Chilling but here in the Valley next to Death Valley the 2014 works great!
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