# A/C



## operator (Jan 2, 2015)

Does turning on the A/C open the vents in the front of the vehicle? i notice a considerable mpg difference when having the A/C off vs having the A/C on.


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## hificruzer226 (Mar 27, 2013)

by vents do you mean the shutters? Do the diesels have shutters?


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## Robby (Mar 1, 2013)

Diesels and ECO's have shutters but in reality those are only worth a very small overall increase in mileage capability and only at higher speeds.

The real culprit is the compressor itself….depending on ambient temperature (which affects operating pressure) it draws anywhere from 5 to 15 horsepower…….takes oats to feed the ponies and you see it as a mileage loss.

These are very efficient compressors used today…..most compressors up until the late eighties and mid nineties would require around thirty horsepower…..the old Frigidare A-6 comes to mind.

Good news for the diesel gang is your engine output can mask the A/C load (other than fuel usage) fairly well…..my ECO…..well, not only does the mileage drop but the poor lil motor loses a lot of 'pep' for lack of a better description.

Rob


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## money_man (Feb 25, 2014)

Turning AC on in my old base cobalt 5 speed would lead to severe downshifting just to stay at highway speeds and 3rd gear to get up hills. 


Sent from the sexy electrician


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## econrey (Jun 7, 2012)

I also noticed pretty drastic power loss in my '12 LT. It was probably easier to manage with the manual, but it wasn't fun. The newer models also have more fan speed settings for the blower, which is really nice.


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## Su8pack1 (Apr 17, 2014)

We took a few hundred mile trip yesterday with the a/c on the whole time, and averaged 44 mpg.


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## jalaner (Dec 28, 2013)

I love the AC on my 2014 CTD. Its very quiet and the coldest of any car I've owned. The fuel economy reduction seems worse in city vs highway. Very useful for the blistering summer in the SE USA.


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## money_man (Feb 25, 2014)

I don't notice any power loss on my ctd. 


Sent from the sexy electrician


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## MP81 (Jul 20, 2015)

Yep, the AC being on in my Cobalt causes the entire car to vibrate at idle - largely due to the fact I have poly engine mounts and trans bushings - but you can definitely feel the power sap when driving it, unless you put your foot into it and get into some boost.

The diesel could care less if the AC is on - doesn't even feel down on power (likely because the torque management limits it to begin with, so with the AC on it just limits it less).


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## spacedout (Dec 7, 2010)

Su8pack1 said:


> We took a few hundred mile trip yesterday with the a/c on the whole time, and averaged 44 mpg.


I put on 1000 hwy miles in the last few days in 90F weather. Driving at highway speeds I have enough RPM or wasted energy I notice little if any MPG loss with the AC on. Now if my car is already cooled off somewhat, I always turn off the AC on my 1.4T when in the city, taking off from stop signs the car is a complete dog.


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## MOTO13 (Mar 26, 2014)

Does the A/C automatically turn on if you have the car on cool setting? I swear my A/C is on when I leave and begin driving because the air is definitely cold...not ambient and I do not have the A/C button pushed.


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## operator (Jan 2, 2015)

https://youtu.be/lT8j910Yzs8

So you all can visually see the difference


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## obermd (Mar 3, 2012)

operator said:


> https://youtu.be/lT8j910Yzs8
> 
> So you all can visually see the difference


Wow. My ECO MT has a much smaller, as in 1 MPG drop when I turn on the A/C on the highway.


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## Aussie (Sep 16, 2012)

The only affect I notice in my CTD is the turbo lag from rest is more obvious. I have automatic a/c and never turn it off and it is winter where I am.


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## Ger8mm (Mar 13, 2014)

Robby said:


> Good news for the diesel gang is your engine output can mask the A/C load


Not true at all, I had several times where the A/C was on and went to merge and the engine didn't even move. Power was drastically cut off. Not all the the time but it has happened more than once.



Let me add on to this, I have a dash camera and I will post a video when it happens again to me.


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## Tomko (Jun 1, 2013)

Ger8mm said:


> Not true at all, I had several times where the A/C was on and went to merge and the engine didn't even move. Power was drastically cut off. Not all the the time but it has happened more than once.
> 
> 
> 
> Let me add on to this, I have a dash camera and I will post a video when it happens again to me.


I've never experienced this.


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## Aussie (Sep 16, 2012)

Ger8mm said:


> Not true at all, I had several times where the A/C was on and went to merge and the engine didn't even move. Power was drastically cut off. Not all the the time but it has happened more than once.
> 
> 
> 
> Let me add on to this, I have a dash camera and I will post a video when it happens again to me.


I know what you mean, but that is just turbo lag and only lasts a couple of seconds and can be reduced by use of a lighter foot until the car starts moving and then you can floor it.


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## Merc6 (Jun 8, 2013)

MOTO13 said:


> Does the A/C automatically turn on if you have the car on cool setting? I swear my A/C is on when I leave and begin driving because the air is definitely cold...not ambient and I do not have the A/C button pushed.


I wish I had those issues. Mine blow hot even when off unless I press recirc. 

Some random Easter egg settings is the farthest blue dot on temp and floor level may turn on stealth A/C mode. Defrost also turns on stealth A/C mode.


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## Ger8mm (Mar 13, 2014)

Aussie said:


> I know what you mean, but that is just turbo lag and only lasts a couple of seconds and can be reduced by use of a lighter foot until the car starts moving and then you can floor it.


This could be it, but it seems to last a little longer, I will wait and post the video when it happens.


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## Merc6 (Jun 8, 2013)

Ger8mm said:


> This could be it, but it seems to last a little longer, I will wait and post the video when it happens.


Hot day in the city even tuned, 1st gear feels like I just tried to launch the car for a dig in 3rd A/C on. Since pollen season is over I have windows down mostly.


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## Kexlox (Nov 4, 2014)

Merc6 said:


> Some random Easter egg settings is the farthest blue dot on temp and floor level may turn on stealth A/C mode. Defrost also turns on stealth A/C mode.


Definitely noticed this. I think that anytime you are on floor only mode the compressor kicks on, no matter what the temperature setting is.


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## MOTO13 (Mar 26, 2014)

Yup. I am on the floor setting 90% of the time. I'll try the vent setting after work. Also, even when venting is set to "floor", some also comes out the dash vents.


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## Merc6 (Jun 8, 2013)

MOTO13 said:


> Yup. I am on the floor setting 90% of the time. I'll try the vent setting after work. Also, even when venting is set to "floor", some also comes out the dash vents.


I stick with bi level, I like to favor floor as that's where my air freshener vent clips are under the seat. Mpg is good with bi level but on hot days and fan off I have to use recirc of hot air comes out at me.


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## MOTO13 (Mar 26, 2014)

Yup, I switched to bi-level this morning, no A/C. I normally get around 46-50 mpg on the ride into work. Today, 55.9.


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