Air conditioning experts, I am roasting.

[ZZT23]

Quick summary:

-03 Vibe GT 280000km
-AC system contains HC-12a Duracool refrigerant
-AC blows warm air (completely inoperative)
-Compressor runs, not seized, AC clutch serviceable
-Minor dent found lower left side of condenser at mounting point to rad support
-No leaks found at visible parts of system with dye check
-System holds pressure, at 45PSI when off
-Low side 30PSI, high side 45PSI when on
-Quick hiss heard from cabin right at startup of AC system
-Suspect receiver dryer at fault

The long story:

The air conditioning in my 03 Pontiac Vibe GT has been quite week ever since I bought it. Last year I tried recharging the system with HC-12a refrigerant (Duracool) and got the AC to blow out 3'C air when it was 25'C outside.

I did not just throw the Duracool into the system and call it a day. The system was evacuated, pulled to a 26"Hg vacuum for an hour (30"Hg is for sea level), and vacuum was maintained after that hour before I decided it was good to recharge. Low side reads constant 30PSI, High side at 125PSI. AC blew nice and cold and life was good.

Lately I have felt that the AC has been slumping again, so I evacuated the refrigerant, pulled vacuum again and saw that vacuum was maintained, so I recharged it again but this time vent temp stayed at only 5'C cooler than outside temp. A few days later, I checked the system again with the manifold gauge, low side and high side were equal at 45PSI which seems reasonable. Turn AC on to see that low side dropped to 30PSI (telling me that compressor sucks refrigerant through itself like it should) but high side did not rise at all.

This seems to tell me that there is a clog between the compressor and the high pressure service port, which includes the receiver dryer and condenser, and it has been accumulated for some time because of the gradual weakening of the system over many months. Looking under the front of the car revealed a minor dent on the condenser (car was never in any kind of accident since I owned it), but if it was the culprit shouldn't the AC have been inactive way before this couple years has gone by? I put dye in the system before I recharge and I did not see any dye showing along the lines and components. The only other possibility I can think of is the receiver dryer needs replacing.

Am I on the right track on diagnosing this problem? The car has 280000km. I have put 50000km into it since I bought it and have not replaced any AC components. Thanks in advance.

[Darell_n]

You are low on gas or the compressor is internally damaged and not pumping much. Try to find somebody to pinpoint the leak with an electronic detector.

[flipstah]

Could be clutch getting stuck. Have issues with the Mini right now similar to this.

[Rat Fink]

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[ZZT23]

Originally posted by Rat Fink
What are your compressor cycles looking like?

Not sure on the properties of that Duracool garbage, but if it was R134 in the system then 45 psi for a static pressure is typically too low and I'd be thinking it was undercharged and/or you have a leak somewhere.

There are no cycles to speak of. It has a Delphi constant pressure compressor and once it gets to a working pressure it sticks there. Duracool recommends using only 40% by weight of their refrigerant compared to how much you would use HFC-134a, which I had measured using a electronic kitchen scale.

[Darell_n]

The standing pressure should be nearly the same of the ambient temperature in Fairenheit. ie: your garage is 65°F so your cold engine off a/c pressure will be around 65 psi.

[RickDaTuner]

if you have a running compressor, and small pressure change between the high and low side, then your compressor vanes are good and done. The compressor wont shut off because the lower pressure sensor still sees enough pressure to cycle on. low side cut off for more vehicles is about 25-30 psi.

even on a low charge, the compressor will cycle, and pull the low side close to zero psi, and then switch off.

there is a definitely a leak, and if you have been charging the system with store bough refrigerant, then you more than likely have forced out all the PAG oil through the leak, which ended up causing the damage.

I would say you need a new compressor, new receiver drier, and a new thermostatic valve, along with a flush.

but prior to all that I would locate the leak.

[ZZT23]

Originally posted by RickDaTuner
if you have a running compressor, and small pressure change between the high and low side, then your compressor vanes are good and done. The compressor wont shut off because the lower pressure sensor still sees enough pressure to cycle on. low side cut off for more vehicles is about 25-30 psi.

even on a low charge, the compressor will cycle, and pull the low side close to zero psi, and then switch off.

there is a definitely a leak, and if you have been charging the system with store bough refrigerant, then you more than likely have forced out all the PAG oil through the leak, which ended up causing the damage.

I would say you need a new compressor, new receiver drier, and a new thermostatic valve, along with a flush.

but prior to all that I would locate the leak.

A failed compressor was actually the first thing that came to mind. I guess I was trying to see if there are other malfunctions that would lead to a similar symptom. Would a failed compressor also not make a pressure change in the low side?

I have never seen the compressor cycle since I first looked into the system, even before I evacuated the refrigerant that came with the car. I totally don't remember the high side pressures back then but I was getting a steady 30PSI with AC running.

When I charged in the store bought stuff, I had also refilled the system with PAG oil. (pouring the oil through the line that leads into the manifold gauge, then connect a can and let them get sucked into the low side line). Unfortunately I could not find factory oil capacity so I only put in about an ounce of it through in fear of putting in too much.

PS: Also the Duracool cans did say the refrigerant comes with "Oil Chill" in them. Is that not compressor oil?

So if I were to get a replacement compressor, would you trust one from the junkyard? I guess what I am trying to ask is if such a malfunction common at all, or do AC compressors usually outlast the life of the car itself if not tampered with.

[RLK]

You do not have a clog in the system. With a clog, the low side usually goes into a vacuum and the high side goes really high and the compressor will vent (around 500psi).

The fact that the compressor does not cycle and the pressures do not change much, after you put a new charge in. I would say that the expansion valve is stuck open. If the valve is stuck open the refrigerant will be flowing too fast through the evaporator and will not evaporate into a gas and thus no cooling. You are essentially pumping liquid refrigerant around the system. Do not put a aftermarket valve in, most of them are re boxed cooling depot ones and they are total garbage. Go and buy a gm one.

The only time I have ever seen a compressor not put out enough pressure is when there is a whole bunch of noise and metal coming out of it.

[ZZT23]

Originally posted by RLK
You do not have a clog in the system. With a clog, the low side usually goes into a vacuum and the high side goes really high and the compressor will vent (around 500psi).

The fact that the compressor does not cycle and the pressures do not change much, after you put a new charge in. I would say that the expansion valve is stuck open. If the valve is stuck open the refrigerant will be flowing too fast through the evaporator and will not evaporate into a gas and thus no cooling. You are essentially pumping liquid refrigerant around the system. Do not put a aftermarket valve in, most of them are re boxed cooling depot ones and they are total garbage. Go and buy a gm one.

The only time I have ever seen a compressor not put out enough pressure is when there is a whole bunch of noise and metal coming out of it.

Mmm interesting....what is usually the cause of TXVs fail open?

[RLK]

They are a thermo controlled valve that has tight tolerances and moves a lot. Sometimes they just wear out. If you pull the valve out there is a disk on the top or the bottom, when you heat or cool that disk you should see the valve open and close. Use a heat gun to close the valve, throw in the freezer for a wile to open the valve.

[revelations]

I dont have any specific help to offer, except that I would have stuck using the OEM refrigerant, knowing what I know now. I am very technical minded (like the OP appears to be) but I dont have the time/energy to learn this specific trade. Getting r134a locally isnt easy either.

I went as far as buying the Duracool, the pressure manifolds and a vacuum puller but from reading up on the various issues online (this one included) I will, instead, be visiting a local shop that has r134a ready for a recharge.

Its around 100$ for a charge so for me its not worth the headache IMO.

[RLK]

Originally posted by revelations
I dont have any specific help to offer, except that I would have stuck using the OEM refrigerant, knowing what I know now. I am very technical minded (like the OP appears to be) but I dont have the time/energy to learn this specific trade. Getting r134a locally isnt easy either.

I went as far as buying the Duracool, the pressure manifolds and a vacuum puller but from reading up on the various issues online (this one included) I will, instead, be visiting a local shop that has r134a ready for a recharge.

Its around 100$ for a charge so for me its not worth the headache IMO.
On top of it, not very many shops will touch his car now. I have very little experience with the AC in a can. I hook the identifier up, if any hydrocarbons or unknown substances show up. I close the hood and say sorry I cannot help you.
It's not actually refrigerant, it's full of propane and butane and a bunch of other things that should not be in a AC system.

[J.M.]

^^ My aunt had her ac compressor changed by one of those gas station mechanic shops and I think they filled it with that stuff you're talking about. When she'd use the AC it would smell like propane/butane.

[Darell_n]

R-134a is close to $4 / lb so you need to make friends with an HVACR guy instead of paying $100 for $6 worth of gas.

[ZZT23]

I read that in Canada you need to have a licence in order to purchase HFC-134a. Knowing I will never have such licence I gave up immediately and started seeing into stuff like Red Tel, Duracool, Freeze -12 etc and just grabbed a few cans off princess auto when it went on sale.

I had the notion that bringing the car in for any HVAC repair/diagnosis for a marginal system would cost very close to if not more than how much I paid for the whole car, that's what got me to give the duracool a shot. Funny thing was that the AC sent out absolutely cold air for the first week or so. Right after filling it up at a 23'C day center vent was blowing out 3'C air!

After putting in my cans of duracool I learned that not too far from the north end of the city there's a store that carries HFC-134a. Not sure of the legality issues of such purchases (read: licence required) so I will keep the place unnamed, but it's across from NAPA east half of the city about 40km north from downtown Calgary:nut:

A new receiver drier just came to my front door, also an aftermarket TXV is due to come in a week (sorry RLK, got it ordered before you chimed in to the topic, will look up prices for a GM one next day). So if I find a way to evacuate whatever that is in my car now, fill it back with HFC-134a, if things were to still not go right, it should be serviceable by a HVAC tech at that point?

Also, are there any PAG oil in a common store that also has dye in the bottle? The hood sticker says RL-897 for oil type, with no mention of amount needed in the system:dunno:

[Darell_n]

Find and fix your leak first or everything else is a complete waste.

[RLK]

Originally posted by ZZT23
I read that in Canada you need to have a licence in order to purchase HFC-134a. Knowing I will never have such licence I gave up immediately and started seeing into stuff like Red Tel, Duracool, Freeze -12 etc and just grabbed a few cans off princess auto when it went on sale.

I had the notion that bringing the car in for any HVAC repair/diagnosis for a marginal system would cost very close to if not more than how much I paid for the whole car, that's what got me to give the duracool a shot. Funny thing was that the AC sent out absolutely cold air for the first week or so. Right after filling it up at a 23'C day center vent was blowing out 3'C air!

After putting in my cans of duracool I learned that not too far from the north end of the city there's a store that carries HFC-134a. Not sure of the legality issues of such purchases (read: licence required) so I will keep the place unnamed, but it's across from NAPA east half of the city about 40km north from downtown Calgary:nut:
:

Is this 134A in a 30 lbs bottle? if not it probably is not actual R-134A. Actual real refrigerant is not available to the general public, so manufactures will package it in a way that shops will use it. like in 30 lbs bottles and not single use cans. AC in a can company's cannot use the actual R-134A designation so they will come up with silly semantics like synthetic 134a when really its just propane.

[RLK]

Originally posted by Darell_n
Find and fix your leak first or everything else is a complete waste.

Are you sure he has a leak? Don't get me wrong, he may. 45psi static pressure is definitely low by R-134 and R-12 standards. But his system does not have the proper refrigerant in it so God knows what the pressures should be.

Static pressure is not really a reflection of the charge level of the system. You can have .5 lbs in a system will turn to gas and bring the pressure up to 70 psi, but in reality there is nothing in the system but gas. I have also pulled 10 lbs out of a system that was meant for 2.5 lbs with a static pressure of about 90 psi.

The way that I look at it is, he charged it the first time. It blew cold so he must have done something right. It starts blowing warm, he recovers the system and recharges it, I'm assuming he did it properly the second time also. If he has the proper amount of charge in the system and the low side is too high and the high side is too low. My best guess would be the compressor has nothing to pump against hence the stuck open expansion valve.

[ZZT23]

Just came back from the Chevy dealership. They can't tell me the price of the TXV. It's a vintage part and they gave me rough ball park of $180.

The HFC-134a labelled can not being HFC-134a sounds pretty ducked up. Looks like I'm stuck with unknown substance forever. Would it be better sticking with that or the duracool? There were videos of people even charging office desk cleaning air cans into their systems because of the supposed propellent being HFC-134a, but I don't think I'll go that far.

[Maxt]

Your vibe requires 8oz of pag-150 oil, unfortunately with the oil chill crap that was in the duracool, plus whatever extra oil you sucked into it with the hose, you are in no mans land with the oil charge, which in an automobile system is critical, because there is so little system volume. As others have suggested you need to start over, fix leaks, flush it out, and see if your compressor even pumps anymore. Once you overcharge a system with oil, and punch the valves out of the compressor in a car a/c system, it becomes an endless loop of compressor changes because extra oil keeps getting left in the system, and then more added with every compressor change and or recharge. The flush is vital to get any trapped oil out of the system so you can start fresh. I've seen people using reclaimed gas saturated with oil to recharge car a/c's and have the same issue, then have it over and over and over again.
You probably won't be able to buy it locally, but I use the rx11 flush .
Maybe Amazon?
https://www.amazon.com/CALGON-4300-08-RX-11-Starter-Kit-2466014/dp/B008FM9GSM/ref=pd_bxgy_201_img_2?ie=UTF8&psc=1&refRID=JQJKZZ6BJ34G276FCBF8


For future reference:
http://www.techchoiceparts.com/refrigerant-and-oil-capacities