Last post on May 13, 2013 at 2:56 PM
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Mazda CX-7, SUV
#250 of 284 Re: 2011 CX7 AC Problem [stantonb1]
Jun 27, 2012 (8:10 am)
I have a 2011 CX9 and I've had nothing but problems with AC. Mazda keeps saying it's normal but when the AC starts blowing hot air when I'm sitting in traffic doesn't seem normal to me. I took it in to a dealership for the 4th time last week because they said they had a fix for it. The fix doesn't work. I'm completly lost as to what to do next. I live in Texas with 110 degrees as the average temp during the summer and my car won't keep cool unless I'm going 60 without stopping. I will NEVER own another Mazda again that's for sure!!!
#251 of 284 Re: 2011 CX7 AC Problem [tself]
Jun 27, 2012 (8:43 am)
Your engine is "tending" toward overheating. Most newer cars, if the engine coolant temperature begins to rise rapidly(??), or rises to a predetermined point below actual overheat, will disable the A/C automatically. Has your dealer checked that the radiator cooling fan(s) are operating properly, going into full high speed early enough to prevent a rise in coolant temperature in heavy stop and go traffic?
#252 of 284 Re: 2011 CX7 AC Problem [tself]
Jun 27, 2012 (8:57 am)
Check to determine if AC blows hot air after vehicle first started from cool overnight parked state with re-circulate off. Check to see if AC blows hot air only after vehicle has been driven a while then parked a short time again re-circulate off. Turn on the re-circulate switch on the AC to bypass the incoming air to prevent hot underhood air from getting into the system and check again. Turn the blower on high while driving and see if the AC eventually does work about ten minutes. Any difference then the problem may be hot underhood engine air overpowers the AC system. Design of system the intake AC air is not coming from outside the car instead from the engine compartment. More you drive the hotter the engine compartment gets and the longer it takes the AC to compensate. If the AC works properly on a cooled overnight system the problem is most likely hot intake air overpowers system. Fix for this problem is to change the AC control module to allow you to set the re-circulate even with the AC compressor is turned off. Not the ideal modification but at least a way to keep the hot air out of the car until the underhood air cools down which takes a bit of driving at decent speed.
#253 of 284 Re: 2011 CX7 AC Problem [tself]
Jun 27, 2012 (8:57 am)
Many owners of the new water cooled Porsche 911's in that climate modify the radiator cooling fan circuits such that they can "pre-emptively" run the radiator cooling fans (2) at full speed using a simple on/off switch.
You can also lower the HEAT load on the engine cooling radiator flowing from the A/C condensor. Bypass the A/C system's reheat/remix mode.
Run the system in recirculate and the max cooling position then use the blower speed to moderate the cabin cooling level. The A/C compressor duty-cycle will be lower then otherwise, less HEAT from the condensor.
#254 of 284 EASY WAY TO CHECK A/C SYSTEM
Jun 27, 2012 (10:48 am)
There is an easy way to check the AC system to determine if the hot air problem is a faulty compressor issue or an overloaded system.
1. Open the glove box remove contents and press side tabs to drop it down.
2. Remove filter cover plate from air intake and remove cabin filter (flexible sides) comes out easily.
3. Turn the AC off and fan on high with re-circulate off set temperature low.
4. Put a thermometer or even your hand into filter slot to check intake air temperature.
5. Compare intake air temperature and to ambient outside air temperature.
Both temperatures should be about the same no noticeable difference whether the engine and underhood compartment is hot or cold. A big temperature difference after the engine has been run hot then left off for a while as compared to when the engine is overnight cool means the intake air is very hot so overpowers the air conditioning system.
To overcome this problem set the re-circulate on and use the AC to cool cabin air instead of intake air.
There is no ready fix for this problem as the air intake pipe opens to the underhood channel on top of the engine at front fo the windshield. So it gets really hot if the vehicle is idles excessively when not enough air gets into the engine compartment to cool it down.
#255 of 284 Re: EASY WAY TO CHECK A/C SYSTEM [e_buster]
Jun 27, 2012 (2:02 pm)
I don't know of any reasonably modern design that doesn't have a GOOD rubber seal between the hood and the firewall in order to keep engine compartment air/atmsophere/heat from entering the A/C outside inlet airflow duct.
#256 of 284 Re: EASY WAY TO CHECK A/C SYSTEM [wwest]
Jun 27, 2012 (3:02 pm)
Regards to the firewall to hood seal, it does not block air from the engine compartment. Plus the location of the intake duct, windshield air chamber and ambient air intake grills causes mostly hot air at low driving speeds.
Notice the firewall top rubber strip extends the width of the windshield except it does not seal the corners of the engine compartment. Look again you will see the intake grills on bottom of the windshield outside are on left and right sides of windshield immediately behind the openings to the engine compartment. Note also the air intake connects to a metal bottomed chamber below the front of the windshield also houses the wiper blade assembly.
Have dismantled the whole lot and determined the hot air from the engine compartment gets rammed into the chamber through the upper corners where the firewall seal does not extend. Plus the metal on the chamber bottom gets extremely hot due to the engine and exhaust pipes being so close underneith.
So the air conditioner intake draws the air from the chamber which can be very hot if the engine has been run long and then stopped. Takes a really long time for the small amount of outside ambient air coming into the windshield drip chamber through the upper grill runs along the bottom of the windshield to not be heated if the chamber was hot.
Grill design is similar on Mazda 3, CX-7 and CX-9 vehicles none of them have a completely sealed firewall. Although the CX-7 GT is and Mazda Speed 3 are the most affected due to the very hot turbo and intercooler located just a couple inches below the windshield air intake chamber.
#257 of 284 Re: EASY WAY TO CHECK A/C SYSTEM [e_buster]
Jun 28, 2012 (6:13 pm)
I don't own a Mazda but a quick check of mine and my neighbors' stable(***) indicates that the more common placement of the seal in question is forward of the cabin's fresh air inflow path.
*** '01 RX300, '95 LS400, '93 Ranger PU, '01 E350 MH, '92 Ford Aerostar.
#258 of 284 AC Still Not COLD from 2011 CX7 & Unit Bangs
Jul 12, 2012 (11:41 am)
On Mon. July 9th took my 2011 CX7 Grand Touring with 5,000 miles to dealer for AC repair. AC was doing nothing not lighting up certainly not cooling. Told fuse had blown to AC and a wire needed to be reconnected. Dealer performed work. AC back on. If CX7 bakes in driveway for a few hours when temps are 90-100F and you first start CX7 AC makes banging noise. AC never seems to get COLD eventually cooler, but not cold after 1/2 hour or longer. At best 68-65F is what comes out of center vent. Our CX7 is black and perhaps this causes it to get hotter than a lighter car, but CX7 stays really hot. Neighbor suggested having side windows tinted; do not know whether this would help. Returning to dealer July 25th. Does any one have any suggestions, am very frustrated.
#259 of 284 Hope My 2011 CX7 AC Is Fixed
Jul 15, 2012 (12:30 pm)
On Sat July 14th driving my 2011 CX7 Grand Touring with my family when AC went dead again. The outside temp was in the 90's. Purely by accident I was by a automobile restoration business and employees came over to CX7 to see if they could help because I had pulled over. I said AC went dead and they offered to take a look. Came to conclusion that my system had air in it. Told that system had been low and refrigerant had been added. Fuse had blow before and dealer replaced a nd re attached lose wire. Restoration owner spent over an hour evacuating my system and refilling with refrigerant. Replaced fuse and "set up my system". While talking with mechanics told of taking into two sepereate Mazda service centers and had AC gone over by these centers. Automobile restoration business would not take money from me. Told they believe they found and corrected problem. Just blown away that owner refused to take any money from me. Owner said that working on my AC was a learning experience for them, glad they could help me. Will send thank you and gift card. G-d bless good mechanics who care. AC has been working well; I think they fixed my CX7 AC correctly. Why couldn't Mazda find the problem? I was in and out of both Mazda service centers in no time, told I was good to go problem was repaired. May good mechanics live very long lives, we certainly need them.