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Mazda CX-7 AC problems



  • wwestwwest Posts: 10,706
    "..coolant reservoir exploding.."


    If that happened to me I would be asking for a replacment engine. Only two reasons I can think of for a coolant reservoir to explode.

    A.) Coolant boiling, STEAM, engine seriously OVER-HEATING.
    B.) Leaking head gasket, pressure of combustion entering the coolant system.

    There is a third, but...

    Rare systems have the pressure cap on the coolant reservoir, in that case if the pressure cap failed...
  • wwestwwest Posts: 10,706
    Sorry, but with many car dealers, TOO many IMMHO, the "soft", diplomatic approach simply does not work.

    If you have a valid complaint that you feel the dealer is not paying appropriate attention to then having a shouting match within earshot of the showroom often works, TOO often, regrettably.
  • Today my CX7 was making a grinding noise and then there was smoke coming from under the hood...its a 2007 with 35,000 miles on it. The dealer told me to bring it in but as I have owned the car for 37 months I am without warranty coverage as AC isn't covered in the 60,000 drive train warranty. What is this about I can't drive the car if its on fire. To me that's a drive train problem.
  • cxrabbitcxrabbit Posts: 134
    50,000 miles and my car came to a grinding smoking halt along the side of the road yesterday. I thought it was on fire and called the fire department. Geico towed it to my local shop for me. Trying to get dealer to cover it now since this is such a wide-spread issue.
  • barb34barb34 Posts: 5
    I had this exact same problem with my 07 CX7 2 years ago when it reached 38K miles. After a local mechanic bypassed the AC we thought we were okay until the parts came in, but it only lasted a couple of hours until the car wouldn't turn over at all. Turned out the AC compressor was shot. Mazda USA was rude and wouldn't help because we are overseas (military), but my stateside dealer helped us diagnose the problem and offered to order and ship the part for $900, they suggested that due to our circumstances we contact a used parts dealer to save time and money. So, we bought a used AC compressor with 5K miles online ($75) and had a local mechanic put it in (300 Euro).

    We are still having problems with the 07 CX7, (engine won't turn over at all now), the AC Compressor was the start of it all for us. It makes me sad, because I really love my car.
  • silviusilviu Posts: 1
    Hi guys,
    I have a problem with my mazda cx 7 and it is related to AC.everything works fine but when i need fresh air from outside and i turn down the temp to 15 i still get warm air,instead of geting fresh air from even in the cool day or nights i need to start the AC to keep the temp.comfy inside the car.Mazda dealer said it perfectly normal but i suspect that is something wrong with the hot air-fresh air valve(or whatever they call it). Any other cars i drove ,when i switch to fresh air i get fresh air from outside.
    Any idea?please HELP
    thank you!
  • pctechpctech Posts: 43
    It IS normal. But in my opinion it is also UNACCEPTABLE. Unfortunately, it's a design problem so we have to live with it.
  • wwestwwest Posts: 10,706
    That's because 190F engine coolant is ALWAYS flowing through the heater core. Most modern day system rely, REQUIRE, that the A/C be fully functional, operational, in order for the system to have full range cabin temperature control.

    The simplist thing to do, fix, is to go to Home Depot and buy a manual water flow shutoff valve and install it in the water line/hose to the cabin heater core.
  • satz24satz24 Posts: 10
    unfortunately that warm air that comes as 'fresh' air is normal on these cars. Very annoying. It seems worst after the car has been parked for some time and then driven again.

    I think it's to do with the turbo heat soaking into the HVAC system. I've had mine back and forth to the dealer to no avail.

    Another problem I've had is when running the AC, warm air comes as the car slows down!!!

    Regarding the suggestion to manually shutoff the water line... I'd be very careful about that. You need to make sure that the cabin heater core is on a separate 'loop', otherwise you could end up disrupting the entire engine coolant flow!
  • pctechpctech Posts: 43
    Being on a trip some 400 miles from home recently, I was waiting for my wife, idling the car with the A/C on, when I noticed a very strong odor of burning rubber. Having read all the horror stories on this forum, I immediately shut off the A/C, hoping that disengaging its clutch would allow the pulley to freewheel, thus possibly avoiding the total failure described so many times here. We nervously made it home and I took the car to my dealer. They checked and, sure enough, the compressor had failed (52,000 miles). Total cost (new compressor, belt and labor) was only $566 plus tax! If it hadn’t been for the warnings from this forum, who knows what could have happened (at the very least, getting stranded in the middle of nowhere)!
  • bcurtisbcurtis Posts: 3
    I had the same problem, and they wanted to charge me $850, but I had already heard about this and challenged the charge upfront. I said since I couldn't drive the car, (my compressor seized and fryed the belt) this is a drive train issue. They compromised, and I paid $225. It really was worth it because the upgraded compressor worked much better than the original.I live in Charleston, SC and am a Realtor, so have clients in the car all the time, and during the hot summer days the old A/C was so low power I used to leave the car running when we looked at homes. Two weeks ago I was in a head on collision with my CX-7 and walked away without a scratch, (the air bags work GREAT!). now I have to decide if I want another CX-7 or try something else. It's fun to drive, and I KNOW it's safe. The only problem I ever had with it was the A/C, and Mazda just needs to "Man Up" and admit the original pump had a design flaw, and take care of their customers...or someone else will.....I'm thinking Chevy now. :)
  • basunndaybasunnday Posts: 3
    edited June 2010
    Just checking out posts about the ac problems. My 2007 Cx7 has 59,300 miles on it and is in shop getting checked out for all multiple noises before the powertrain warranty runs out. They are finding lots of issues, but none that are covered. I wasn't aware the ac had widespread problems, just knew mine was not working good at low mph, and the compressor sounded very noisy when it kicked in. They advised me to replace it now before I was stuck on the side of the road. Quoted me at $760 plus charging and taxes. See some are getting some help on that, and there seems to be a wide range of prices on what people are getting charged. Now I don't want to have a wreck to get a different car, but it wouldn't bother me if someone stole it or something.
  • bcurtisbcurtis Posts: 3
    Keep complaining. I did and got it down to $225. The replacement is a better design and cools better too.
    The good news is my CX7 was totaled last month, and I bought a Toyota Prius.
    50mpg, ice cold A/C, and it runs on regular gas. ;)
  • e_bustere_buster Posts: 5
    Have significant issues with hot air blowing always with the AC turned off. Plus the AC has trouble to cool on hot days. These symptoms are parroted by a number of the previous posts. Seems the problem is prevalent in every CX-7 with automatic climate control and dealers tell you to just live with it by turning on the AC.

    After considerable diagnosis and taking apart the under-hood shroud assembly, it turns out the HVAC climate control system works pretty much correctly. My CX-7 only minor fault is the blend door, bottom left regulator arm as you look through the glove box opening, does not fully shut so there is slight heat from air leaking through the heater core. Most of the hot air however comes from the engine cowl and windshield shroud assemble. The primary airflow into the cabin from the outside setting actually comes indirectly from the engine compartment and not outside. This happens because there is a metal bottom channel under the leading edge of the windshield covered by a plastic shroud assembly the width of the dash from which the heater draws air. The channel is not effectively sealed and the backside of the under-hood firewall seal is open at the both ends of the shroud. There are some perforations along the window side of plastic shroud but they are mostly not effective.

    If you doubt, just put a thermocouple type furnace or air conditioner thermometer into the crack above the cabin air filter and watch how the temperature changes as the car operates. You will observe the hot air does not in fact come from the heater assembly but instead from the heater blower air inlet up under the windshield.

    When the CX-7 is moving outside air is drawn into the engine compartment through the radiator being accordingly heated. There is a large plastic cover on the underside of the compartment so not much air enters there. Compartment air is accordingly rammed through the openings at the under-hood back corners directly into the windshield channel. The channel is metal located above the turbo, exhaust pipes and inter-cooler so it gets very hot the longer the engine runs. So the very hot channel passes mostly engine compartment air already hot into the cabin heater inlet. And it does so always which means the AC compressor and system must compensate for the additional inlet heat.

    Collateral problems are the climate control system assumes the inlet temperature to be the ambient temperature as shown on the dash gauge. Assume the system would malfunction so not necessarily blow enough cool air. There is also the problem of the AC system being over worked which probably leads to premature compressor failure. There is also the issue of health risk from cabin occupants always breathing air from the engine compartment. On the up side, the air re-circulation function works independently to close off the outside air inlet. Just click the switch on and you block the under-hood hot air from entering the cabin. Only catch is you then have no ventilation and must open the windows.

    Short story, the climate control system does not in fact draw air from the outside when set to do so. Instead it draws air mostly from the hot engine compartment whereby the air conditioner must be always on to compensate.

    A disappointing proposition as it looks there is no way to correct the problem. And there looks to be dozens of CX7 owners who are bothered by the issue. Unless the engineers at Mazda to provide a modified plastic shroud assembly with a sealed cowl and outside grate perforations to prevent the air from the windshield channel and essentially engine compartment air from entering the cabin. Such a modification is surely possible and would not be terribly costly to install en mass as every CX7 would need one.

    Sorry, there is no fix and nothing actually wrong with the HVAC. The fellow at 166 had the story correct except the cause is complicated and issue more substantial than most of us would expect.
  • pctechpctech Posts: 43
    The extensive analysis and explanation by e buster is wonderful! This may be a bit of a stretch, but does it look like it might be possible for the owner to make some or all of the suggested mods to at least improve on things?
  • e_bustere_buster Posts: 5
    edited June 2010
    Today the outside temperature here was 75F both on the CX7 ambient readout and according to the weather report. When my CX7 was started the HVAC inlet air temperature, measured immediately above the cabin air filter, showed as 75F and stayed there for at least 10 minutes. After an hour of city driving with a few stops between the HVAC inlet air registered 105F about. Under-hood temperatures are upwards of 135F at the firewall bezel just below the windshield behind the inter-cooler. The lowest possible temperature my CX7 air conditioner could manage was eventually 65F. Which is just not enough to cool the vehicle much below 75F in the sunshine with the windows closed.

    The AC unit was therefore working to cool incoming air at 105F instead of outside air at 75F. Which means the compressor has to run constantly just to keep up with pretty modest outside temperatures. With the re-circulation turned on, so no external air is used and inside already cool air is cooled again, the AC unit can eventually cool air to 35F but then only at lower outside temperatures. Assuming the under-hood air temperature would always be greater than the outside temperature, it would be a whole lot better if the AC was fed with outside air directly. It seems obvious the AC unit would then have cooling capacity to handle outside temperatures equal to the 105F it currently gets at 75F. As you can see, the hotter the air you put into the system the higher the temperature of the cooled air output.

    Unfortunately, Mazda vehicles are pretty much the same design with a plastic covered metal cowl structure under the windshield with inadequate firewall seals and, with very hot engines jammed so tightly in under-hood compartments, the design does not work. The result is the HVAC units work inordinately hard to compensate for often hot inlet air temperatures. Which means vehicles have inadequate cooling much of the time and hot air when the AC is turned off.
  • wwestwwest Posts: 10,706
    You missed something....

    Unlike HVAC systems of a few years ago these new systems have no shutoff for HOT, >190F, coolant flowing through the heater core. So the radiant heating effects from the heater core will ALWAYS have adverse effects of the efficiency of the A/C to cool the cabin.

    Buy and install a manual coolant flow shutoff valve so the HOT coolant can be prevented from HEATING the entire area surrounding the heater core.

    Also. Most modern day automatic climate control systems are designed to prevent slight discomfort due to TOO cool airflow to your face and upper body. To that end once the cabin air/atmosphere is cooled to your setpoint or closely nearby the blower speed will be significantly reduced, the reheat/remix vane door will be adjusted to provide more WARMISH airflow. Airflow just barely cool enough to maintain the cabin atmosphere nearby the setpoint.

    Many of these systems will even open the windshield and footwell ducts to outlet airflow in order to more widely disperse the cooling airflow to prevent discomfort.

    Absent installing the shutoff the highest A/C efficiency can be attained via the MAXIMUM cooling setting and use of the blower speed to regulate the cabin comfort level.

    Plus: The Human Comfort equation involves more than the surrounding air temperature, radiant heating, or lack thereof, has as much to do with our comfort level as does the atmosphere surrounding us. These highly slanted windshields, with such DEEP dash TOP surface areas are no help at all. To prevent reflections on the windshield that would interfere with the driver's forward vision these are often in a very dark color shade. Absorbing HIGH heat levels in the HOT sun, moving or stationary.

    What is needed is a dash top surface covering that has a fresnel effect, reflective forward but non-reflective otherwise.
  • wwestwwest Posts: 10,706
    edited June 2010
    "...HVAC inlet air registered 105F about..."

    Are you sure you weren't measuring radiant heating effects along with airflow temperature..?? Or even radiant effect moreso than airflow temperature..??

    The inlet airflow itself might well have remained in the 75F range while the radiant effects were the result of the 135F engine compartment.
  • ws46ws46 Posts: 27
    29K miles 07' CX-7 GT AWD (still under bumper to bumper warranty)

    I live in nyc and we drove to Montreal that's about 6-7 hours away for the fourth of July vacation. The AC stopped working on the return trip to nyc (Monday) about 3 hours into the drive. It just blew hot air and it smelled of burnt plastic/rubber, exactly as described by many others on this thread. (I've read every one of the postings here.)
    We stopped using the AC and looked for the nearest Mazda dealer as we were driving down, but they were going to be closing early, and we weren't going to make it before their closing time.

    Driving in the heat really sucks [non-permissible content removed].. and we stopped for gas with about 150 miles to go. Filled up the tank, and the car wouldn't start. So had to call the NY thruway tow truck, to get it off of the thru-way property to a location where the Mazda roadside Tow truck could pick up the car. (NY Thruway towing fee was about $95, which will be reimbursed by Mazda)

    (Also called my insurance GEICO's roadside assistance, but that was going to be more expensive, so went ahead with Mazda's roadside service.)

    They took the car to an overnight facility and delivered it to the nearest Mazda dealership in Poughkeepsie, which is 1 1/2 - 2 hrs away from where I live.

    Mazda Poughkeepsie ordered parts for the car and they will get them in 4 to 7 days.

    They are replacing the AC compressor and the belt. Should they be replacing anything else??

    I am now without a car for about a week. They have a loaner car for me at the dealership or their local Enterprise rental, but nothing in nyc.

    Called Mazda USA and they said that they would reimburse car rental up to $30 per day, but try finding a car rental at that price in Manhattan.

    But they will probably cover the cost of the MetroNorth Rail ticket to pickup the car, so I'll just live without a car until I take the chu-chu train to Poughkeepsie to pickup my repaired car.

    I am debating on getting the 30K maintenance done in Poughkeepsie too since it's already going to be at a dealer. They were quoting around $380 for the maintenance. Is that a reasonable price?

    I tried to see if Mazda USA or Poughkeepsie dealership would be able to get me a discount for the maintenance, but so far, no good news..

    Did anyone else experience their car failing to start far from home like this?

    Is there a better way to handle situations like this?

    The rep at Mazda USA wasn't rude, but not nice either.. defensive, and trying to give as little as he can, and wouldn't even guarantee the Metronorth ticket reimbursement but said that he'll "most likely" approve it when I filed for reimbursement.. not the kind of customer service I was expecting when it's been a rather stressful day being stranded due to their faulty car.

    I guess I am not driving a Lexus or a Benz where I would expect that they would provide better service for situations like this.. who knows.

    Now I am wondering if I should get some sort of extended warranty. Any recommendations?

    Anyways, it's been helpful to read everyone's post, and I'll update after I get all this sorted out and get the car back. Hopefully my updates will help someone else, as this thread has helped me so far.

  • re0876re0876 Posts: 3
    I encourage all who have problems to file a claim here:
  • pctechpctech Posts: 43
    Complaint submitted today. I urge others to do so as well.
  • steverstever Posts: 52,572
    Bummer about the vacation (guess it helps that you were heading home at that point).

    About your 30K maintenance question, the Edmunds Maintenance Guide will tell you what it should cost in various US zip codes.
  • ws46ws46 Posts: 27
    Yes, the maintenace at 30K should be much cheaper.. maybe I'll do some of the work myself, or at least shop around a little.

    I've filed a complaint to:
    just doing my part.
  • sdbobo619sdbobo619 Posts: 13
    I rec. Replacing the belt tensioner why your in there, shouldnt be hardly any extra labor. After replacing my AC system the first time the belt tensior broke 3 weeks later and again left me stranded and out 500.00
  • I have a CX 7 with 47,000 miles on it, love the handling of the car, love the look, wish I could feel like the car was dependable. My story is like many others. Went to wedding this weekend 300 miles from home. Was driving to the church, car made funny sounds, thought at first it was the brakes (squeaking like wet brakes) but then it stopped so I thought nothing, but then I turned on the air conditioner, was okay for about five minutes, then the smoke started and the smells began. I had to pull over on my way to wedding (I was the maid of honor) in my dress and all. I truly thought the car was on fire. I turned off engine, popped hood and was hoping for no flames, again all in my long dress. I saw the belt was shredded, looked like the damage was minimal, I was lucky. Must have been a real sight to all onlookers. I remembered seeing postings about the air in this car, turned off air and prayed it would bring me home. We returned today. Mazda just called, they will cover the repairs. I am fortunate I know, would have been about $1000, now I need to call them tomorrow and ask about which part they are replacing with. I like my car but am feeling weary about it.
  • fliifastfliifast Posts: 6
    Did you have an extended coverage?
  • No, I had not purchased the extended warranty. My dealer, who I use for all service, knows me well. I have gone there with the threads from here and used it for them to check different things on my Mazda. Service manager said usually they cover the labor costs but I would have had to pay for parts, because I have been a loyal customer they covered all of it. This car has been in the shop several times, one time for three weeks, they gave me a car on that one. Took car home yesterday, air is working well and because of this forum I made sure they checked the belt tension-er as well, feeling educated :)
  • On the way from Idaho to our vacation in California, our AC started blowing hot air. We pulled over to check and found the compressor had a bearing noise. There were no service stations open @ 5 pm on a Saturday in the town we were in (and no Mazda dealers there either), so we decided it was less of a gamble to try to drive 400 miles back home rather than worry about getting stuck farther away.

    Approx 2 hours shy of making it back home - the car started putting out tons of smoke! We immediately pulled over and jumped out. The friction caused by the compressor or clutch started to melt our serpentine belt. Luckily we were in a small town. Towed it the rest of the way to prevent further damage.

    Now it is Sunday and we are waiting for the dealership to open Monday morning to see whether they will cover it as a warranty and if they have the parts in stock or not. Seems like they never do.

    We have had so many issues with this car that the service department knows me by name when I pull in. Problems so far include: Engine mount; Replaced Transmission & throttle body (at 30,000 miles - took 3 visits for them to decide to replace it - then I had to take it back for so the car could "relearn" how to roll down the front passenger window); the Map Sensor; and now this!

    The other frustrating thing is I just had the car in for the 45,000 check up 2 weeks ago (with a return visit because some plastic dropped down next to the blower motor when they changed the cabin air filter - which caused a ticking noise when I ran the vent/ac).

    Definitely not planning to recommend nor buy another Mazda in the future. At least NOT WITHOUT THE EXTENDED WARRANTY! Fortunately, all the repairs so far have been covered by warranty, but the amount of time and inconvenience have been excessive with this car. I could tolerate the little things like the trim pieces breaking off for whatever reason. After 2 fixes, I just gave up on it.
  • cx7drivercx7driver Posts: 2
    edited August 2010
    Mazda really needs to recall the air compressor on the 2007 and 2008 models.

    There are way too many complaints for the issue to be owners not taking care of their vehicles as one poster suggested. I'm a big believer in regular maintenance and my 2008 Mazda CX-7 (purchased in Dec. 2007) blew the air compressor this weekend at 42,000 miles. Luckily, I was not too many miles from my home when it happened.

    I have a service appointment Monday morning to have the air compressor and belt replaced. May end up being the one and only Mazda I ever own....

    Report your complaint on this website
  • nwcx7nwcx7 Posts: 1
    While I have been fortunate so far with my 2007 CX7's A/C compressor, I have spoken at length with my dealer's service manager about the number of complaints. On Wednesday, he called to inform me that Mazda is extending the A/C warranty on specific 2007 VINs to 5-years/60,000 miles. A letter from the manufacturer is forthcoming and you all might call your service departments with any questions; not sure if they will cover retroactively, but that sure would be a great public relations move.
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