[amg2000]

Of course immediately turned off A/C after a few minutes and mechanic drained it and charged to appropriate pressure. Everything's working fine running A/C for 2 hours --- but warning to others. Those cheap ($40) charge kits from Pep boys have unreliable pressure sensors or something.

If anyone knows what the temporary smoke/smell was let me know. I read in other forums that overcharged air conditioners always shake the car.

 

[amg2000]

And no I didn't really need to charge it. Just thought it wasn't super cool, even though it was probably as cool as it will get.

 

[somms]

AC compressor $2400

FWIW: Please keep in mind that this 3-phase alternating current compressor used in the Volt in order to keep the high voltage battery as well as the cabin cooled is normally covered under the Voltec 8yr warranty. You may want to keep the fact you attempted a home brew recharge of this compressor under your hat so to speak!

 

[amg2000]

I wonder how long it takes to know whether it damaged the compressor.

Curiosity and this link are to blame https://www.carcarekiosk.com/video/2013_Chevrolet_Volt_1.4L_4_Cyl./air_conditioner/recharge_freon

Actually I'm guessing it's fine since a fault error would have probably come on in light of how important this part is.

 

[voganni]

Overcharging any refrigeration system is very risky. If the compressor sees any liquid refrigerant it will stall or, in the case of electric residential equipment, trip an internal high pressure overload. Be sure your system is properly charged and checked per the manual. It is a VERY expensive compressor!

 

[amg2000]

wow i'm so stupid. Read this

https://macsworldwide.wordpress.com...hen-recharging-ac-systems-on-hybrid-vehicles/

Some hybrid vehicles use air conditioning compressors that are operated by an electric motor instead of a drive belt. The motor’s insulated windings are immersed in the compressor’s lubricating oil. The oils used in these compressors have high dielectric (non-conductive) properties. DENSO has produced a chart showing that as little as 1% contamination by an improper oil can affect the dielectric properties. If a different type of oil somehow makes its way into one of these compressors, and if the insulation on the windings has become damaged or compromised, a variety of problems may occur. . . . in service bulletins, some hybrid vehicle manufacturers state that all of the refrigeration system components must be replaced if oil cross contamination has occurred.

 

[freshcut]

Yep, I also read that you can't use the small cans of 134a at the auto parts store either since they contain a small amount of oil, and that you must fill with a 30# cylinder. I have a fair bit of automotive a/c experience, including complete rebuilds but the warnings on the Volt system have left me to just decide any work will get done with the dealer.

 

[amg2000]

Yep, I also read that you can't use the small cans of 134a at the auto parts store either since they contain a small amount of oil, and that you must fill with a 30# cylinder. I have a fair bit of automotive a/c experience, including complete rebuilds but the warnings on the Volt system have left me to just decide any work will get done with the dealer.

Yeah, I've been googling around a bit and they say the PAG oil (the oil that my "all-in-one" charger had) DID NOT immediately cause voltage problems in a Prius's compressor (which is similar to a Volt's). The tester said he took a 95k mile Prius, drained its compressor oil and used PAG in its place, and drove it 8k miles with no apparent problem (but he then took the PAG out and switched back to the Prius certified oil to be safe). So I should be OK for a while but this was so dumb on my part. The A/C was working more or less fine just not completely freezing.

Let my stupidity be a lesson to others. What's funny is the person who made the video above tells you to add A/C Pro brand freon charger
https://www.carcarekiosk.com/video/2013_Chevrolet_Volt_1.4L_4_Cyl./air_conditioner/recharge_freon

BUT A/C PRO SAYS TO NEVER USE THEIR PRODUCT IN A VOLT!!!! http://acprocold.com/blog/car-tipstricks/shouldnt-use-ac-pro/

 

[El Dobro]

The Volt and the other GM vehicles with electric A/C compressors use POE oil.

 

[voganni]

The Volt uses a variable output compressor, and often is not running at full cooling capacity. My 2013 can get pretty darn cold when it wants to, so I just let it do its thing. If you got the wrong oil out after only a short time you're probably OK. Takes a while for the insulation to break down. A similar thing can happen in HVAC compressors if the refrigeration system is not evacuated well enough after brazing fittings together, or they aren't brazed with a nitrogen purge. The residue inside the copper lines eventually damages the compressor's insulation as it forms an acidic compound. Can take years though.

 

[srmarti]

We miss anything on how stupid trying the DIY an AC system without understanding the details?

 

[amg2000]

The Volt uses a variable output compressor, and often is not running at full cooling capacity. My 2013 can get pretty darn cold when it wants to, so I just let it do its thing. If you got the wrong oil out after only a short time you're probably OK. Takes a while for the insulation to break down. A similar thing can happen in HVAC compressors if the refrigeration system is not evacuated well enough after brazing fittings together, or they aren't brazed with a nitrogen purge. The residue inside the copper lines eventually damages the compressor's insulation as it forms an acidic compound. Can take years though.

I did the dealership's flush using the GM a/c flushing machine. It takes out all of the freon gas and adds freon + oil back in, I think. As I understand, most of the oil "travels with" the freon, so most of the old oil was taken out. The dealer didn't really know much about it other than to say "we connected it to the GM machine it took everything out and added new freon back."

Any way, not sure what's going to happen but as I understand this is pretty much the best you can do short of replacing every a/c freon-touching component, so . . .

 

[Steverino]

And no I didn't really need to charge it. Just thought it wasn't super cool, even though it was probably as cool as it will get.

I believe the rule of thumb is the A/C can only drop the inside temp by 20°F compared to outside temps. A/C is not the same as refrigeration. But someone in the trade may know more. I really haven't looked into it in detail other than expecting 40°F air to blow out you car A/C on a 110°F day is likely not going to happen.

 

[samotlietuvis]

Of course immediately turned off A/C after a few minutes and mechanic drained it and charged to appropriate pressure. Everything's working fine running A/C for 2 hours --- but warning to others. Those cheap ($40) charge kits from Pep boys have unreliable pressure sensors or something.

If anyone knows what the temporary smoke/smell was let me know. I read in other forums that overcharged air conditioners always shake the car.

Your mechanic should have removed all the Freon, pulled vacuum, and added exact amount of Freon using weight. I would not do anything else for the variable speed compressor with TXV valve... Charging by pressure is not a wise thing to do. And - get pure Freon without oil or any additives. It is not too late to do the procedure I described - better than replacing $2k+ compressor down the line...

 

[freshcut]

I don't think 55 out of the vent is an unreasonable figure. With 134a you generally won't see less than about 37 inside the evaporator. By the time the temperature is exchanged through the evaporator to the air, and to the vent opening you'll have even more loss of temperature. Granted this is normally on a 80-90 degree day. 100+ likely won't see less than about 65 out of the vent, possibly higher if the battery is also drawing from the A/C system. Truth be told though, most modern day A/C systems are VERY particular about charge quantity. a couple ounces over or under results in severe loss of cooling capacity. Most modern systems use 2 pounds or less. Not like the old R-12 systems that held 4 pounds and were much more forgiving with over or under charged systems.

 

[amg2000]

Your mechanic should have removed all the Freon, pulled vacuum, and added exact amount of Freon using weight. I would not do anything else for the variable speed compressor with TXV valve... Charging by pressure is not a wise thing to do. And - get pure Freon without oil or any additives. It is not too late to do the procedure I described - better than replacing $2k+ compressor down the line...

I'm pretty sure that's what he did? He did the standard GM a/c service using the GM a/c machine which sucks everything out, flushes the system with something, and adds new stuff in. Regardless, this GM service station said they can't really do anything more. It'll probably be fine.

My only concern is the cheap pep boys stuff was a mix of freon and oil, so I added about 1.5-2 oz of PAG oil into the system. As I understand, most of the oil in the system travels with the freon gas, so when the GM machine removed all the gas it removed most of that oil too. But not all of the oil was removed since some of it settles and doesn't travel with the gas.

 

[amg2000]

I don't think 55 out of the vent is an unreasonable figure. With 134a you generally won't see less than about 37 inside the evaporator. By the time the temperature is exchanged through the evaporator to the air, and to the vent opening you'll have even more loss of temperature. Granted this is normally on a 80-90 degree day. 100+ likely won't see less than about 65 out of the vent, possibly higher if the battery is also drawing from the A/C system. Truth be told though, most modern day A/C systems are VERY particular about charge quantity. a couple ounces over or under results in severe loss of cooling capacity. Most modern systems use 2 pounds or less. Not like the old R-12 systems that held 4 pounds and were much more forgiving with over or under charged systems.

My last car was a luxury convertible whose a/c was so freezing cold you could feel cool-ish with the top down in a 90 degree day. They must have done something special with that.

 

[freshcut]

Some are more efficient than others. Of course system size plays a big role but keep in mind, the size of the system also impacts how much energy is used to operate it. A luxury car doesn't exactly strive to be efficient like a Volt.

 

[hellsop]

I believe the rule of thumb is the A/C can only drop the inside temp by 20°F compared to outside temps. A/C is not the same as refrigeration. But someone in the trade may know more. I really haven't looked into it in detail other than expecting 40°F air to blow out you car A/C on a 110°F day is likely not going to happen.

I'd imagine that a good deal of that is simply that cars recirculate a lot less air than refrigerators do, and eventually that percentage of hot, un-recirculated air is going to bringing in enough moisture that the humidity control is going to start backing off to avoid freezing the condenser coils.