# I think my air conditioner clutch is dragging when it is off



## albow77 (Feb 18, 2012)

I have noticed that there is cold air blowing out the vents when it is warmer outside. The frist time was about a month or so ago and it got 87 degs out. I was driving on the interstate with a light jacket on and noticed that I wasn't getting hot. Felt the vent and there was really cold air blowing out of it. I had the fan speed on low and turned it to high and the air got warm fast. I then turned the ac on and then it got cold. I noticed that my MPG gauge really dropped so I turned it off again. The air got warm so I turned the fan speed to low and the air was warm coming out the vent. About 10 miles later I checked the vents and very cold air again. This leads me to believe that my AC clutch is draging. I have noticed on the foggy mornings that the water is condensing on the outside of the windshield also when the vent is on. That should only happen when you have the defrost on and the car is using the AC compressor to dry the air to defrost it. Wondering if anyone has noticed that also. I have averaged 40 MPG so far but wondering what it would be with out the clutch dragging and killing my mileage.


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## NickD (Dec 10, 2011)

This has been going on for over twenty years now, ever since GM decided to use an interference fit for that driven clutch plate. It can either creep in or out, in like yours, will drag with even the AC switched off. Out too far, AC won't even work at all.

I have no idea why the chief engineer approved of this, I personally hate it, a special puller/installer tool is required to set that gap to precisely 20 mils between the idler pulley and that driven clutch plate. So far, have three of those, they keep on changing the puller/installer just enough so the one you have won't work. Don't even know if my third tool will work on the Cruze. But bet it won't.

Even a +/- 0.0001 inch shaft tolerance is too loose for an interference fit, if minus, plate can shift, if plus, can't even get the darn thing off. With the latter have to do that to replace that idler pulley very limited lubricated bearing. They made that job miserable by peening that bearing in instead of using a retainer ring.

Everyone else is using shims, plate wear is normal, just remove a 12 mm bolt, slide off the clutch plate, remove a shim or two to get the correct gap, slide it back on again and torque that bolt. But have to say with the V-5 variable displacement compressor that runs all the time as opposed to that crazy cycling system, clutch plate wear has become very rare.

If under warranty, your dealer should be able to adjust your clutch, should only take him about five minutes. If out of warranty, depends upon which crook you go to, some will insist you need a new compressor when that adjustment may be all that is required.

It really pays to know all this stuff, seen some people get robbed for over 2000 bucks in lieu of a five minute adjustment.


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## iKermit (Dec 13, 2010)

NickD said:


> Wall of text!
> 
> 
> > How the **** do you know so much? Did you happen to just say "Hey let me look at idler pulley and clutch plate and adjust it" What is your job, if your an engineer then all of this makes sense.


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## NickD (Dec 10, 2011)

Worked in the field for 36 years, degreed electronics engineer, but got stuck in charging and ignition system designs. Never was one to brag about sitting through a course in differential equations, so kiss my butt kind of thing. Was more of a hands on engineer crawling all over semi's, passenger vehicles, and even farm tractors. 

Worked with mechanical, material, physicists, manual, and legal departments, was good at liability suits and used frequently as an expert witness, believed in being fair and honest. So I received a good handle on all aspects of the automobile. Use to have a photographic memory, but tell people, it way over exposed today. Memorizing 500 IC part numbers was easy, today that count is 750,000, a bit too much.

Also FCC, FAA, 608 and 609 certified, later so I can buy a can of R-12 or R-22, have a bunch of AC equipment, been actually active in this since 1964. Maintaining five airport navigational ground systems to supplement my measly SS income. One of my kids had a precondition, kicked him off my health insurance, and blew my retirement. Four years ago, all this GM stuff was moved to China, so that ended that. Did at first receive a lot of calls about this junk, but was helpless to do anything about it.

With my experience in liability suits, reason why I am critical on modifications, but see no harm in weather stripping.


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## MetallicaMatt (Mar 26, 2012)

I've owned my Cruze for 3 weeks now. Read this post last night.

Drive home today, I had the climate control set to manual, had the temp set to LO and the fans all the way up. It was 69* outside. All of a sudden it got COLD. Then it would go away, then back on again, over and over. Long story short, it seemed the a/c would kick on for about 30 seconds, then off again. "Auto" was off, "A/C" was off, "AQS" was off.

I turned the fans all the way up, they would blow normal outside air for a couple minutes, then get freezing cold, then the fans would idle almost completely off....then they would jump back to high again at normal temperature???

NOT happy. New car and I just started working (6) 12's :/

Mine is a 2012 LTZ with autoclimate. When I turned it to auto, the fans idled down (because it was freezing inside) and stayed normal.

Forgot to mention this whole time while in manual mode, I continued to play with the temperature settings, but made no difference.


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## iCruze2 (Dec 16, 2011)

albow77 said:


> I have noticed that there is cold air blowing out the vents when it is warmer outside. The frist time was about a month or so ago and it got 87 degs out. I was driving on the interstate with a light jacket on and noticed that I wasn't getting hot. Felt the vent and there was really cold air blowing out of it. I had the fan speed on low and turned it to high and the air got warm fast. I then turned the ac on and then it got cold. I noticed that my MPG gauge really dropped so I turned it off again. The air got warm so I turned the fan speed to low and the air was warm coming out the vent. About 10 miles later I checked the vents and very cold air again. This leads me to believe that my AC clutch is draging. I have noticed on the foggy mornings that the water is condensing on the outside of the windshield also when the vent is on. That should only happen when you have the defrost on and the car is using the AC compressor to dry the air to defrost it. Wondering if anyone has noticed that also. I have averaged 40 MPG so far but wondering what it would be with out the clutch dragging and killing my mileage.


Mine is doing the same...And I only average 36mpg on highway


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## iKermit (Dec 13, 2010)

NickD said:


> .
> 
> Worked with mechanical, material, physicists, manual, and legal departments, was good at liability suits and used frequently as an expert witness, believed in being fair and honest. So I received a good handle on all aspects of the automobile. Use to have a photographic memory, but tell people, it way over exposed today. Memorizing 500 IC part numbers was easy, today that count is 750,000, a bit too much.
> .


I commend you on your experience. Wish my generation was more exploring like you guys.


I am in the electronics field, selling IC's and all the equipment to solder etc, (and thousands of other things). And i want to run away from it, FAR away from it. Can't stand it, not meant for me.


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## MetallicaMatt (Mar 26, 2012)

I have been averaging 34.5mpg highway. My trip to work is about 20-25 miles of flat roads at 68mph. The rest is flat at around 55-60mph.


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## Dale_K (Jul 16, 2011)

There is a known issue with the Cruze A/C compressor but I don't know if it affects the climate cooling function. On some Cruze cars, the A/C compressor makes a repetitive pulsing or low roaring noise at idle. I noticed it on mine the very first day I owned it and complained to my dealer. The noise would go away when I turned on the A/C system but would come back when I turned it off. It was kind of like the compressor was running a little bit when the system was supposed to be off. This same situation has happend to a number of other folks and the fix is a replacement compressor. GM has issued a bulletin about it on the the GM Techlink website.

I don't know if this problem exists on your car but you could listen for the sound that goes away when the A/C is turned on. My car seemed to actually cool OK when the problem was active. I can't tell any cooling difference with the new compressor installed. I have an LS with the manual temperature controls. 

As far as the A/C clutch goes, I could not detect any clutch operation on my car, either before or after the compressor replacement. GM made a big deal about the ECO model having a clutched type compressor but seemed to imply the non-ECO models might not use a clutch. On my car there is no click and no visible action at the compressor when you turn the fan on for A/C with the snowflake button active. The compressor shaft appears to spin all the time.


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## NickD (Dec 10, 2011)

EPA range of 31-45 mpg with a mean of 38 mpg is on the window sticker for my 2012 2LT. EPA finally started doing that when it occurred to them they are demanding 155 different blends of gasoline. Never saw a report from them on using ethanol. From my experience, they can drop that 31 down to 17 mpg if you are unfortunate enough to get a bad mix.

I found it most economical to pay 5% more for the best highest octane gas that has resulted in over a 20% improvement in mpg. Higher octane gas burns slower, with anti-knock sensors, get far more spark advance without preignition. But kind of dead meat now with winterized cracked oxygenated reformulated winter gas Best I can do is 37-38 mpg, but that Lordstown gas on the first tank gave me 44 mpg.

Then which pump I choose, sometimes the fuel used is dead on or can be as far as 10% off, so is it the gauge or the accuracy of the pump? For years, car gas was 120,000 BTU per gallon, today, anywhere from 90,000 to 106,000 BTU. Aviation gas is still at 120K, but that can cost as much as seven bucks a gallon.

Buying gasoline today is tantamount to buy a lottery ticket. And practically all EPA regulated emission controls is after the fact, where it should be before the fact. This is too long to get into, but what can you say about any agency that is put in charge because they helped the current president get elected.

For me ACC was a requirement, wasn't bad in the 60's as you had some control. A vacuum operated heat valve was used that blocked all coolant flow to the heater core. That is history, today all heater cores are working at full blast and dependent upon a plastic blend door to determine heat. An with any automated systems, you are losing control to a silly-con diode. Wouldn't be bad if this happens a block away, one my ACC controls went haywire on a hot summer day during a major thunderstorm so was given the choice of either drowning or being baked alive. Least in the old days, could pull that vacuum line off the heater valve and block it with a bandaid. Totally helpless today.

Manual system in the Cruise is not much better, all soft touch controls commanding the BCM that activated either electrical motors or vacuum actuators. Sure wish they stuck with real cables to do the same thing. A reason for apprehension for even buying one, but have survived this in the past. Some mercy with vacuum operated actuators, just can't open or close a door with no damage, electric motors and associated electronics burn up.

This is primarily the result of having an icy rain with the vehicle left outside where moisture in these doors freezes them up, perhaps another reason why your dealer cannot find the problem. Any is debris build up, least the Cruze has a filter to help to prevent that.

Diagnostics for these systems is limited to an open or a short, nothing about the non-linear characteristics of the ambient, solar, or in-car sensor that can cause all kinds of problems. Then the controller is an 89 cent microcontroller fed by firmware stored in flashram. Again an EPA push to make it easier for the manufacturer to update this firmware, but screw you consumer.

And the guys working on these things certainly are not certified technicians. Another thing I really hate is insulation displacement connectors, saves the wire stripping operation for a good solid crimp. Here a tiny pointed piece of brass is suppose to make good contact with unplated bare copper wire that turns green. The result of this is very erratic behavior highly dependent on the ambient temperature and another reason why your dealer can't find the problem. 

Don't blame engineers for this, either had to go this route or they will find somebody else. Least with the old engineers, these new kids don't even have enough brains to change a burnt out light bulb without runnin a computer simulation first.

Just some background, but hardly solves your problem, just take it back to your dealer. Love that expression, "dey all do dat".


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## ChevyCruzeLTZ (Apr 7, 2011)

The LTZ with auto climate control has an interior moisture sensor, from what I can tell this sensor can turn the A/C compressor on at any time to dry the air, just like when you have the windshield defog vents open.


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## MetallicaMatt (Mar 26, 2012)

^^ Good to know, as it was raining and muggy when I noticed this, BUT I was in manual mode at the time, not Automatic. When in manual with the snowflake/a/c button off, the compressor shouldn't have kicked on all the time....or so I would think...


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## GoldenCruze (Dec 18, 2011)

Hmm... software issue?


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## NickD (Dec 10, 2011)

No question about the moisture sensor, from the Cruze shop manual:

"
*Windshield Temperature and Inside Moisture Sensor*

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.
This sensor assembly provides information about:

 •Relative humidity level at windshield (compartment side)
 
 •Temperature of the windshield inside (compartment side)
 
 •Temperature of the humidity sensor element
 The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the passenger compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient."

If I can go back to 1965, with proven silicon transistors and an engineering management headed by all mechanical engineers, was absolutely impossible to convince them to replace ignition or voltage regulator points with a transistor that could switch trillion of times without failure. Wasn't done until the 1972 model year with a two transistor circuit using NASA thick film technology.

How that has changed and how I have changed over the years. With some vehicles having over 488 pages of solid state, do not test circuit diagrams, would be happy to go back to just ignition points when you run into problems. 

For some strange reason, back in about the mid-60's when automatic climate control first came out, did permit using one transistor to operate the new blend door motor circuit. Ha, a one transistor automatic climate control system, rest was all electromechanical. Use to like those, you could see what was going on.

04 Cavalier used an old fashion cable system for the mode and blend doors, wife forced it when the doors were frozen and bent a cable, but that was only a 12 buck and five minute repair. Told her not to do that, running the engine for about 2-3 minutes is enough to make switching modes easy.

Previous ACC systems used brushed motors that would burn up if stalled. I see the Cruze is using all stepping motors, if stalled, they normally don't burn up, just don't step. Cavalier also used fixed resistors for the blower motor speeds, again 12 bucks if they burn up. Cruze uses a power MOSFET PWM motor control that runs 112 bucks. Hope this time if the blower motor freezes up, blows the fuse instead of the overpriced module.

Was a bit weary of the Cruze MVAC system, is really nice when it works, just hope, it keeps on working. No, I am not going to take mine all apart and analyze it, still under warranty.

But I do like to know what I have, or got stuck with.


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## MetallicaMatt (Mar 26, 2012)

....so in summary...what we are experiencing is normal, or no?

Today was perfectly dry, not very humid and I didn't notice it (didn't have it on very long).

Either way, If I tell it to leave the a/c off, it should leave it off in my opinion, instead of getting frozen every 2 minutes.


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## Chevy Customer Care (Oct 29, 2011)

albow77 said:


> I have noticed that there is cold air blowing out the vents when it is warmer outside. The frist time was about a month or so ago and it got 87 degs out. I was driving on the interstate with a light jacket on and noticed that I wasn't getting hot. Felt the vent and there was really cold air blowing out of it. I had the fan speed on low and turned it to high and the air got warm fast. I then turned the ac on and then it got cold. I noticed that my MPG gauge really dropped so I turned it off again. The air got warm so I turned the fan speed to low and the air was warm coming out the vent. About 10 miles later I checked the vents and very cold air again. This leads me to believe that my AC clutch is draging. I have noticed on the foggy mornings that the water is condensing on the outside of the windshield also when the vent is on. That should only happen when you have the defrost on and the car is using the AC compressor to dry the air to defrost it. Wondering if anyone has noticed that also. I have averaged 40 MPG so far but wondering what it would be with out the clutch dragging and killing my mileage.



albow77,
I would like to apologize for the issues that you have been experiencing with your vehicle. I would suggest that you take your vehicle into your dealership. If you would like me to contact your local dealership please send me a PM with your name, phone number, VIN and the name of your dealership. I would be happy to assist you with this. Either way, please keep me posted on this issue. If you have any further questions please feel free to contact me.
Thank you,
Stacy Chevrolet Customer Service


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## ChevyCruzeLTZ (Apr 7, 2011)

MetallicaMatt said:


> ....so in summary...what we are experiencing is normal, or no?
> 
> Today was perfectly dry, not very humid and I didn't notice it (didn't have it on very long).
> 
> Either way, If I tell it to leave the a/c off, it should leave it off in my opinion, instead of getting frozen every 2 minutes.



I believe it is normal and we only have limited manual control over the system. If the A/C system is operating when it is not being commanded on it should set a DTC, I would just ask them to check for that at your next service.


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## Big Tom (Mar 8, 2011)

MetallicaMatt said:


> ....so in summary...what we are experiencing is normal, or no?
> 
> Today was perfectly dry, not very humid and I didn't notice it (didn't have it on very long).
> 
> Either way, If I tell it to leave the a/c off, it should leave it off in my opinion, instead of getting frozen every 2 minutes.


Very true. I bet when they do the EPA testing it stays off.


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## Chevy Customer Care (Oct 29, 2011)

MetallicaMatt said:


> I've owned my Cruze for 3 weeks now. Read this post last night.
> 
> Drive home today, I had the climate control set to manual, had the temp set to LO and the fans all the way up. It was 69* outside. All of a sudden it got COLD. Then it would go away, then back on again, over and over. Long story short, it seemed the a/c would kick on for about 30 seconds, then off again. "Auto" was off, "A/C" was off, "AQS" was off.
> 
> ...




MetallicaMatt,
I would like to apologize for the issue that you are experiencing with your Cruze. I would suggest that you take your vehicle into your local dealership and have them look into this for you. Please keep me posted on your progress with your dealer. If you have any other questions, comments or concerns please feel free to contact me.
Thank you,
Stacy Chevrolet Customer Service


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## MetallicaMatt (Mar 26, 2012)

Thank you Stacy!

I am very happy with the dealership that I purchased the vehicle from. Hopefully their service is just as good!

I will keep you updated.


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