CX-5 heater core issues discussed on another Mazda forum
- Thread starter Jmaz
- Start date
I would, and not wait until 10 year mark. Regardless of what Mazda says I'm starting to put the 10 year coolant changeout in the same category as "lifetime transmission fluid". Meaning that the intervals are too long for both. Also curious how the Mazda FL22 coolant is good for 10 years initially but then needs changed every 5 years thereafter.
**** Yesterday, at 70,900 miles I changed out my coolant (2X drain and fill -- 1 gallon each time) with the Zerex Asian Green. It was done at the 4 year and ~27 k mile mark since the last changeout with same coolant at ~44k miles.
I didn't wait until 5 years because it was a good opportunity when replacing upper& lower radiator hoses and thermostat. Fun job. They were on for 10+ years (and can go for 15 or more years) and although still OK, I wanted replacements so as to last for the duration of my use of the vehicle. Labor is expensive and parts aren't getting any cheaper so trying to avoid (way far) future failures and expense.
Also did (1) drain and fill with Mazda FZ transmission fluid while waiting for the coolant to drain, so that's done. * note here* I couldn't believe how dark the fluid was looked (rather black) after doing 2X D&F just 27K miles ago.
New serpentine and water pump belts are going to be installed also. Those presently are original with 10+ years on them and want the replacements to be the last set installed also.
I still have to replace the valve cover gasket since discovering a small amount of oil around the base of #1 spark plug. Oil control valve shows no leakage (fingers crossed).
All are OEM Mazda branded parts purchased online from a Mazda dealer.
Reasons for doing this are (as mentioned above) the increasing costs of labor and parts , so I DIY whatever I can DIY. The second reason is the inescapable trajectory of aging and 5 or more years from now I may not be able or willing to tackle some of these jobs. Gotta "Git 'er done".
Finally*** like to put in a "plug" for Jake Sweeney Mazda in Cincinnati. The member here, @HyFlyer, recommended them and their prices are good. I paid shipping but no tax for all of the parts, which was nice. Carry on.
**** Yesterday, at 70,900 miles I changed out my coolant (2X drain and fill -- 1 gallon each time) with the Zerex Asian Green. It was done at the 4 year and ~27 k mile mark since the last changeout with same coolant at ~44k miles.
I didn't wait until 5 years because it was a good opportunity when replacing upper& lower radiator hoses and thermostat. Fun job. They were on for 10+ years (and can go for 15 or more years) and although still OK, I wanted replacements so as to last for the duration of my use of the vehicle. Labor is expensive and parts aren't getting any cheaper so trying to avoid (way far) future failures and expense.
Also did (1) drain and fill with Mazda FZ transmission fluid while waiting for the coolant to drain, so that's done. * note here* I couldn't believe how dark the fluid was looked (rather black) after doing 2X D&F just 27K miles ago.
New serpentine and water pump belts are going to be installed also. Those presently are original with 10+ years on them and want the replacements to be the last set installed also.
I still have to replace the valve cover gasket since discovering a small amount of oil around the base of #1 spark plug. Oil control valve shows no leakage (fingers crossed).
All are OEM Mazda branded parts purchased online from a Mazda dealer.
Reasons for doing this are (as mentioned above) the increasing costs of labor and parts , so I DIY whatever I can DIY. The second reason is the inescapable trajectory of aging and 5 or more years from now I may not be able or willing to tackle some of these jobs. Gotta "Git 'er done".
Finally*** like to put in a "plug" for Jake Sweeney Mazda in Cincinnati. The member here, @HyFlyer, recommended them and their prices are good. I paid shipping but no tax for all of the parts, which was nice. Carry on.
- :
- CX-5 Sport 16.5 6M
I don't think I've ever had any issues with getting heat, but I'm going to flush mine out (at 50K miles, 8 years).
I'm wondering if it's safe to buy some kind of coolant from Amazon. I don't have a dealer in my town.
I think while I'm flushing it I might see about draining the heater core directly from the firewall and see what the coolant looks like.
I'm wondering if it's safe to buy some kind of coolant from Amazon. I don't have a dealer in my town.
I think while I'm flushing it I might see about draining the heater core directly from the firewall and see what the coolant looks like.
I can't recall a case where pre-mature coolant service (in-conflict with service guide) ever caused an issue. Loose argument from some would be waste and cost but at this point I don't personally agree with the long term manufacturer recommendations.
It seems more or less based on lower maintenance cost of ownership compared to other vehicles than anything that is truly good for the vehicle.
It seems more or less based on lower maintenance cost of ownership compared to other vehicles than anything that is truly good for the vehicle.
TBH… I’d have to look in forums.. but can’t frankly remember someone with a leaking water pump on their CX-5 in the last 10 years..not saying there aren’t a few but so rare I can’t remember offhand.
Unless mine starts noticeably dripping coolant I have no reason to swap water pumps. A weeping water pump is rarely a catastrophic issue unless one never monitors their coolant levels over a long period of time.
Unless mine starts noticeably dripping coolant I have no reason to swap water pumps. A weeping water pump is rarely a catastrophic issue unless one never monitors their coolant levels over a long period of time.
Both of my coolant changeouts at 44k and ~71 k were done with Zerex Asian premix bought at O'Reilly Auto parts for ~ $21 gallon. Nearby Advance Auto didn't stock it. I don't think local Autozone carries it either.
I wouldn't think the coolant from the heater core would be any different than anywhere else in the system. This isn't the old systems with a heat control valve that you could adjust to regulate the amount of coolant into the heater core. New systems have the coolant always flowing through the heater core and the heat admitted into the passenger compartment is regulated using blend doors to admit or block heat flow.
I'm using Zerex Asian pre-mix as well... in conflict to many here but I'm fine with decision and will report any coolant failures I experience in the future.
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Brief update, 2 weeks from the service visit to flush, trouble code remains clear...crossing fingers. What little I can see of the fluid looks good. I'll check the heat on drive later today. If it works out will definitely keep it on a schedule to replace coolant.
Per other post above, sure the coolant runs through the heater core all the time, my old Toyota truck has a broken blend door in the hvac and when it decided to open the blend door despite cold setting in summer there's a blast of heat. Unrelated issue for here it has to with a broken electrical control panel and I'm too cheap to fix that part and I just unplug the wiring harness that control the motor moving the blend door open/close when it randomly closes. I'll snap the wire harness back together when I want the blend door to work and let the heat back into the cab in the winter. The knob control doesn't work and it has a mind of its own randomly swinging the blend door open or closed when the wiring is connected.
Per other post above, sure the coolant runs through the heater core all the time, my old Toyota truck has a broken blend door in the hvac and when it decided to open the blend door despite cold setting in summer there's a blast of heat. Unrelated issue for here it has to with a broken electrical control panel and I'm too cheap to fix that part and I just unplug the wiring harness that control the motor moving the blend door open/close when it randomly closes. I'll snap the wire harness back together when I want the blend door to work and let the heat back into the cab in the winter. The knob control doesn't work and it has a mind of its own randomly swinging the blend door open or closed when the wiring is connected.
Back from the drive today.. drat.. I think the core remains somewhat blocked. I drove for about an hour on an errand during visit with the owner ran the temp and fan up in the cab and could tell a difference in the heat present from airflow toward the footwells on passenger side much warmer than driver. With the car parked I opened the hood and put my fingers across the upper hose and it was plenty hot to the touch but the lower hose was definitely much cooler, warm not nearly as hot as the upper hose. Oh well, past the grief, will look into getting the core replaced past the summer vacation. The trouble code hasn't reappeared yet but that's probably a matter of time or sample cycles.
Mazda Fun to drive when I can, makes my own rides feel like I'm driving a sponge. It reminds me a bit of the drive of original Honda Passport which was Isuzu Rodeo. That past SUV design required an understanding of high center of gravity and physics or at least read the sun visor warning before driving.
I'm thinking this might be more subtly hiding under the radar of the sensor not so noticed with partial blockage.
Hello. I'm new to this forum but I too am having a heater core issue. I have a 2016 Mazda CX-5 Grand Touring that I bought in June 2015. Around 92,000 miles in Spring 2022, the check engine light came on and the dealership diagnosed it as a heater core failure. I had GEICO Mechanical Breakdown Insurance at the time, and it covered the car for 7 years or 100,000 miles so I was able to replace the heater core for $250. In March 2024, at approximately 119,200 miles, the check engine light illuminated again. I wasn't able to get it diagnosed in March and didn't notice any engine performance issues and the code scan came up normal at Auto Zone. The light went off and on for the past three months. I didn't get it checked again at the dealership until earlier this month because it is now due for its annual inspection. Well, at the dealership they advised it was the heater core again. The error code according to my scanning tool is PO11A Engine Coolant Temperature Sensor 1/2 Correlation. Dealership said it could be a software issue and they updated the PCM. However, the check engine light came back on within three days. Besides that, they also told me I need to replace the belt tensioner and drive belt (there is an odd noise usually around 30 mph sort of like hissing) and rear shocks (because the shock mounts are allegedly broken). All of this at the dealership would run me likely $4,000. The car is only worth $7,500 likely on a trade. Needless to say, I declined all of the work and am having it inspected at a local mechanic this week. I feel like Mazda should warranty the heater core but according to the paperwork they only warranty for 1 year or 12,000 miles. I really liked my CX-5 but this heater core thing really burns me up (pun intended) and I'm not sure I could buy another Mazda as my next car. I'm leaning towards the Honda CR-V (even with the CVT engine that car people seem to distaste).
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- CX-5 Sport 16.5 6M
I wonder if GEICO should honor the heater core warranty. They actually replaced it and two years later it's clogged again?
By the way, how is the heater output?
Belts and tensioner might need replaced but that should be a reasonably priced repair.
Broken shock mounts happen but I believe a new set of Mazda rear structs might include new mounts.
The cost of the heater core replacement is several thousand if the dash has to be completely removed.
By the way, how is the heater output?
Belts and tensioner might need replaced but that should be a reasonably priced repair.
Broken shock mounts happen but I believe a new set of Mazda rear structs might include new mounts.
The cost of the heater core replacement is several thousand if the dash has to be completely removed.
I think they will only cover repairs until 100,000 miles. I can't find anything about a warranty period through GEICO's MBI program. It's not the same as if it was in an accident and repairs were performed.
I didn't notice any heater or air conditioning issues until yesterday. It's been in the mid 90's here. Yesterday, the air conditioner was blowing a little bit of hot air. It was set at 60 degrees but the temperature coming out of the vents was not even close to that. I shut it off for a little bit and then tried it again and it was better.
I'm not sure that the noise I'm hearing is the tensioner. I read something last night that it's something to do with the axle. Although maybe replacing the tensioner makes sense when replacing the belt.
New shocks come with new mounts. What sort of annoyed me was that the Mazda Technician said the shocks were okay and they sell the mounts separately, but they don't separate. The service manager said the technicians use an air hammer to do the repair so the shocks have to be replaced.
The first heater core repair was about $1800 I think, but I only had to pay $250 for the MBI deductible. Has Mazda fixed this issue with the new models?
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- CX-5 Sport 16.5 6M
If the heater core was replaced and the cooling system refilled with fresh, approved Mazda coolant it shouldn't need attention now. There was a STB issued concerning the lack of rust preventative additives in the factory fill coolant that caused the clogging of the heater core. The replacement procedure calls for replacing the coolant 2x after the heater core replacement to insure all of the coolant is replaced with the proper mixture.
Has the Mazda service manager shown you these broken strut mounts?
Have you considered taking you car to another shop to confirm any of these suggestions to repair your car? Check this forum for more information about strut mounts and heater core repair/replacement.
Has the Mazda service manager shown you these broken strut mounts?
Have you considered taking you car to another shop to confirm any of these suggestions to repair your car? Check this forum for more information about strut mounts and heater core repair/replacement.
Just had the coolant drained/filled at the dealer this morning.
Asked the Service Mgr. about TSB 07-007/17 which is the heater core blockage. He said he never
heard anything about it.
They say that about every problem that pops up.
They have to be the least knowledgeable about the products they sell/service or they're told to disavow all questions about possible problems.
This was in our 16 not our 19.
Asked the Service Mgr. about TSB 07-007/17 which is the heater core blockage. He said he never
heard anything about it.
They say that about every problem that pops up.
They have to be the least knowledgeable about the products they sell/service or they're told to disavow all questions about possible problems.
This was in our 16 not our 19.
On my receipt at 92,500 miles they wrote: "Technician was able to verify customer concern and found the heater core to be restricted. Recommended to replace. Technician replaced heater core per insurance authorization. Cleared codes. Checked repair, road tested, and verified all to be okay at this time." Invoice shows they installed a heater core for $501.22 and 2 things of Mazda Cool(ant) at $54.08 each. Why it is failing again at 122,000+ miles doesn't make any sense.
I saw an inspection video which they say shows the broken strut mounts.
I have an appointment tomorrow afternoon at an independent mechanic.
Sounds about right. I feel that if there isn't a class action lawsuit filed, they aren't interested in fixing the problems with their cars unless the customer is paying their exorbitant hourly labor charges.
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- CX-5 Sport 16.5 6M
There are a number of threads on the subject of heater core and FL22 problems and solutions.
I’m a little confused… if you had blockage the AC shouldn’t be impacted unless the sensor fault detecting the temp discrepancy with heater core somehow put the AC into some kind of limp mode
