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Discussion Starter · #1 · (Edited)
My 2012 Volt (113k mi) is at the dealer for an unrelated check engine repair (another thread...) but I am taking the opportunity to have them check the HVAC system for a problem with very weak airflow. Maybe I am mis-remembering but I just don't recall the AC on Auto being this anemic (on either Eco or Comfort). In the summer heat, the car is having trouble staying comfortable because even though cold, the airflow from the dash is just so poor on Auto. It's better if you crank the fan up to high, on Comfort, which is noisy, but shouldn't the car know to cool down on high and adjust to sun load while on Auto then throttle up and down with the cabin temperature?

Also I notice that the airflow from the dash is higher when in recirc mode vs outside air mode.

The car does not have a cabin filter in it.

The dealer says the Freon is ok and that the mechanic didn't find anything blocking anything and that the system "is fine."

1.) Is this issue a common condition in the Volt?

2.) How can one tell if the evaporator or heater core is clogged with debris, dirt, etc? Can it be cleaned? (how?).

3.) Is there a specific, measurable airflow volume that is supposed to come out of the vents, to determine if there is a blockage? Service manual?

I am concerned the mechanic may have been rushed and overlooked something in the service manual or TSBs. Do you have to dismantle the dash to see/clean the evaporator? The loaner car I got, an Impala, put out hurricane levels of ice cold air on AC. My Volt eeks out a fraction of that, resulting in cold fingers, but with the rest of me and my passengers sweating into the seats.... Almost like the sun sensor and temp sensors do nothing...
 

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The AC airflow is dependent on whether you're using Comfort or Eco and the speed to which the fan is set. If you're using Comfort and the fan is set to a higher rate the AC should be good.
 

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How long have you had the car? Has it always been this way - if you've had it for awhile and it is now acting different and much less effective, you obviously have an issue.

I recently acquired a 2013 and my AC works very well. I live in the Dallas, TX, area and we've had humid 100 degree plus days.

Typically, I run mine in Auto and Comfort for the first five minutes, then switch it to Auto and ECO - I sometimes change it from Auto to point to face and feet while in ECO. I have to turn the temp up to 74 or 75 cuz it does get cold in the car.

Try using the precondition on the app and see if it's more effective while charging and before you get in the car - I find that precondition turns it on full blast then when I start the car, it defaults it to the last setting I had.

Good luck.
 

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Try pulling the HVAC fuse for about 30 seconds. When you put it back in, you should hear the air flow controllers reset. They may be in the wrong position and blowing the air some where else instead of the face vents.
 

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I believe there is also a config menu setting for how fast to run the fan in auto mode.

Gunk in the evaporator coils is also a possibility. Leaves, etc. can get sucked in, or mold can grow in there. Access for cleaning is a major problem. There are evaporator cleaner products that you can spray in there through a long hose for mold reduction.
 

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There are 3 auto-fan speeds in the Config menu. Perhaps you had a higher setting and then the car's programming got reset at the dealer or something.

You could also shop-vac the area where the cabin air filter housing is, perhaps there is a buildup of leaves, etc in this area.
 

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Discussion Starter · #7 ·
There are 3 auto-fan speeds in the Config menu. Perhaps you had a higher setting and then the car's programming got reset at the dealer or something.

You could also shop-vac the area where the cabin air filter housing is, perhaps there is a buildup of leaves, etc in this area.

I will check the auto fan setting and see if that helps, thanks!

In case it is the evaporator being partially clogged, my quick review online shows that evaporator removal and cleaning is a huge undertaking in many cars (I assume the Volt is even worse to access). Does GM/Delco make a spray foam type evaporator cleaner that can be sprayed through the cabin air filter access door onto the evaporator? I know BG makes such a cleaner but cant find anything from GM. GM makes a spray on evaporator coil "coating" to prevent mold, but I cant find any reference to an actual coil cleaner.

Any ideas?
 

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In addition to everything else that has been mentioned, try cracking your rear windows just a tiny bit and see if the airflow improves.

The reason I mention it is that in another car I had the "cabin relief vents" had these rubber flaps that eventually glued themselves shut and the car became a sealed drum to the extent that it was actually hard to close the doors or hatch properly.

I have no idea where or what construction the body vents on a Volt are, but I know mine is already pretty damned "tight" and if something was blocking those exhaust vents you aren't going to get a lot of outside air moving into the car (but recirc would work fine).
 

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For AC I find that Auto does not do it for me. I manually set the fan speed usually about 3 once the cabin has cooled a bit. Also manually set the recirculate button. Airflow is affected by which setting the recirculate button is on. I usually keep it on recirculate which does limit airflow a bit.
 

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Discussion Starter · #10 ·
For AC I find that Auto does not do it for me. I manually set the fan speed usually about 3 once the cabin has cooled a bit. Also manually set the recirculate button. Airflow is affected by which setting the recirculate button is on. I usually keep it on recirculate which does limit airflow a bit.
I'm beginning to think the G1 Volt just has a marginal design for Auto A/C, lowering the fan speed too fast in order to maximize electric savings, even with a high sun load and hot interior surfaces remaining from sitting outside in the heat. Didn't the engineers think that the back seat passengers would need some airflow?

The only thing else that could be a problem is that, aside from possible debris in the ducts or evaporator, it could be HVAC sensor problems or a software issue, but without a shop manual, I have no means to properly troubleshoot the system. The dealer, I am afraid, just did a quick check of the Freon levels and didn't investigate much deeper than that.
 

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The spray in evaporator cleaner will not help much if there are leafs in the system. These cleaners are more for mold type smells and do little for actual cleaning. You say there is no cabin filter, do you mean that it was removed? You may also want to remove the blower motor to inspect the fan to make sure there is no debris inside of it. Normally if there is, you would get a vibration when the fan is high speeds. With the blower removed, you can reach in towards the evaporator core to feel for leafs of debris. The blower motor is located under the passengers side of the dash and held in with 3 screws. The best thing to do first is compare the system to another volt of the same year and go from there.
 

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I'm beginning to think the G1 Volt just has a marginal design for Auto A/C, lowering the fan speed too fast in order to maximize electric savings, even with a high sun load and hot interior surfaces remaining from sitting outside in the heat. Didn't the engineers think that the back seat passengers would need some airflow?

The only thing else that could be a problem is that, aside from possible debris in the ducts or evaporator, it could be HVAC sensor problems or a software issue, but without a shop manual, I have no means to properly troubleshoot the system. The dealer, I am afraid, just did a quick check of the Freon levels and didn't investigate much deeper than that.
Well if you use comfort mode and point the vents to the back it will get cold air to the back seats quickly. However, I have often wished it had vents in the center console like some other larger cars.
 

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My 2013 does not have weak AC. We have had heat indexes over 100 for a good part of the summer, and I love to blast the AC. My car has AC that is about as good as any car I have ever had. Definitely gets the job done. I can't speak from personal experience about the back seats, but I'm not getting complaints from back there. If yours is not working well, I think there is a problem rather than it just being designed that way.
 
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