2016 CX-9 Signature leaking coolant

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Mazda 2 touring
Hey guys,

This weekend the CX-9 started leaking and burning coolant. I took a look at the engine bay and I couldn’t find a leak around the any of the hoses. However, it seems to be leaking from the firewall side. I’ve made an appointment with the dealer, for this coming Saturday. I’ve been reading through the forum and this seems to be a problem, that is affecting the 2016 model years.

I’ll update as I learn more.

2016 signature
39,000 miles
 
Solution
Hey guys,

So I dropped off the CX9 today and this is a known issue (2016 model years). The service assistant confirmed this, even before I took in the car. Once the car was inspected, they determined a new engine would be required. However, they are in back order and I’ll get more information on Monday. I’ll try to get photos of the engine and more details if possible.

I think my build date is March or April 2016.
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2010 CX-9 GT
Whatever it turns out to be, please try to get a detailed diagnosis and, better yet, photos of what exactly is broken. There's been a number of reports on this forum about mysterious coolant leaks but in most of the cases the precise location (head, block, etc) has not ever been revealed.
 
Upvote 0
:
Mazda 2 touring
Hey guys,

So I dropped off the CX9 today and this is a known issue (2016 model years). The service assistant confirmed this, even before I took in the car. Once the car was inspected, they determined a new engine would be required. However, they are in back order and I’ll get more information on Monday. I’ll try to get photos of the engine and more details if possible.

I think my build date is March or April 2016.
 
Upvote 1
Solution

speed3chris1

2021 Signature CX-9
That really sucks!!!! I traded my 2016 Sig in for a 2021 Sig. I had 27,000 miles on it. I never had that problem but I did have a problem with oil dilution from fuel. I only have 2,000 miles on my 2021. Can you ask the dealer if your problem is just for the 2016 or does it cover other years to. Thanks in advance.
 
Upvote 0
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2005 Mazda3
This seems to be a reoccurring issue with the 2nd gen CX-9's, unfortunately... we can't say it's all of them, but more and more keep popping up, and Mazda seems to acknowledge this issue. The 2020(+..including 2021) had slight changes to the engine... slight bump in HP and Torque.. also a different part number for the engine block, so perhaps Mazda realized they needed to beef it up a bit more and added some more power while they were at it.

I made a thread regarding the reliability of the 2nd gen CX-9, while trying to track common issues:


..as this SUV still catches my attention for my next potential vehicle... one day perhaps(I admire how Mazda's drive, with a touch of luxury and class... only other thing I could ask for is longetivity as I favor to keep a vehicle for a long time if it was built right and has the right features...) hopefully they figured out the dreaded engine coolant leak issue(leading to a brand new motor) with the slight updates they have made to the motor.
 
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andrewnds

2021 CX-5 Signature, 2012 Mazdaspeed3 Tech Pkg.
This seems to be a reoccurring issue with the 2nd gen CX-9's, unfortunately... we can't say it's all of them, but more and more keep popping up, and Mazda seems to acknowledge this issue. The 2020(+..including 2021) had slight changes to the engine... slight bump in HP and Torque.. also a different part number for the engine block, so perhaps Mazda realized they needed to beef it up a bit more and added some more power while they were at it.

I made a thread regarding the reliability of the 2nd gen CX-9, while trying to track common issues:


..as this SUV still catches my attention for my next potential vehicle... one day perhaps(I admire how Mazda's drive, with a touch of luxury and class... only other thing I could ask for is longetivity as I favor to keep a vehicle for a long time if it was built right and has the right features...) hopefully they figured out the dreaded engine coolant leak issue(leading to a brand new motor) with the slight updates they have made to the motor.
I researched a lot before I made the purchase of my CX-5, but since I have the previous gen Mazda turbo engine in my Speed3 and that motor has been rock solid overall I didn't think I needed to research Mazda's new turbo engines until I came across your thread and this one. I was aware of how good the N/A 2.5 is overall, but since the CX-9 was the first recipient of the turbo engine I've been in the CX-9 groups and forums trying to find more information on these engines. I do take comfort in knowing I have a 2021MY though. The current gen Signature trim Mazda's are the best blend of sport, luxury, capability and comfort all wrapped in a tried and true package without getting into the German brands with premium prices and lack of reliablility, which is what sold it big time for me.

This CX-5 is my 4th Mazda, and so far they've all been flawless when it comes to reliablility, even with the Ford/Mazda models like my old Tribute. I seriously hope Mazda knows what they're doing when it comes to the 2.5T.
 
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Upvote 0
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2005 Mazda3
I seriously hope Mazda knows what they're doing when it comes to the 2.5T.

Having been involved in many large Engineering projects myself, I can say that there's a lot that goes on behind closed doors, :p, pressures and deadlines to release products on time despite some "defects" we'll say. What I can say is if you see some consistency in the outcomes, which I attribute to management and the team they work with, we can hopefully expect similar deliveries.

Mazda is a small company, so I'm sure there are many pressures(budget, less people, pressure to perform with that small budget.... pride of the management and engineers at stake to please upper stake holders, etc...)... but they do seem to get some things right most of the time, though I don't know how the new CEO will lead things or even how much say he has(some companies run differently behind the scene, and sometimes the CEO is more of a figure head rather than an actual "Captain" steering the ship).

What I'm glad to hear and see is that Mazda at least acknowledges the issue and seems to be proactive about it. Worse case scenario for those who currently have a pre 2020MY 2nd gen CX-9 is to get an extended drivetrain warranty while they still can, and perhaps drive the car hard during that time... so if the problem does come up, it'll hopefully be triggered during the warranty time, haha.

I agree with what you have to say about Mazda.. regarding how the car drives, the luxury, etc... while not having reliability issues or exorbitant added costs of German cars(not to mention German cars are difficult to work on...purposefully to make the consumer take the car to be serviced exclusively at the dealership)... Mazda's were generally a good mix/balance, gave good value... it's why I'm still a Mazda fan. I have friends and people I know with VW's, BMW's, Mercedes', etc... where the car had major issues during warranty but seemed to be reoccurring, thus it was in their interest to get rid of the cars within 3 years(or when the warranty expires).. I don't want that headache, me personally I like sticking with a well built car for the long haul when deemed worthy(you get used to/comfortable with the setup...).
 
Upvote 0
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Mazda 2 touring
The head gasket was the problem, however Mazda replaced the entire engine because it was still under warranty. (Dec 2020 engine). I love this car. So I hope it was a first run problem.
 

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Winnipeg Canada
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2017 CX-9 GT
That's interesting. Someone here said they need to remove the engine for a head gasket. I'm wondering if that's because they would need to machine both the aluminum head and block. That would also change the compression ratio (unless a thicker gasket can compensate). Maybe that's why they replace the engine as a head gasket job changes the engine somewhat.

Back in my Supra driving days, the 7mgte motor was kinda known for blowing head gaskets. A new head bolt torque spec from Toyota supposedly solved it. Those that blew a head gasket would often replace it with a metal one, but that required machining the aluminum head and was fairly expensive. We might be facing something similar here.
 
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andrewnds

2021 CX-5 Signature, 2012 Mazdaspeed3 Tech Pkg.
The head gasket was the problem, however Mazda replaced the entire engine because it was still under warranty. (Dec 2020 engine). I love this car. So I hope it was a first run problem.
What do you mean by Dec 2020 engine? Is that the date the new engine was installed, or manufactured?
 
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I just took my 2016 GT into the dealership for a coolant leak in the rear of the engine today (4/10/2021). I purchased the car used in 2019 with an extended warranty. My dealer has not been able to locate the source of the leak after using a scope and running a pressure test. After reading the threads on here about the 2016 CX-9 coolant leak problems, it's seeming like I will need an engine replacement as well. The last update we got was they were not wanting to disassemble around where the leak is coming from because the warranty will not fully cover the labor required to do that, which is 3-4 hours. My dealer will not give a loaner car or rental car until the leak is diagnosed so now I am left without a vehicle until that happens. Hoping that the issue can be diagnosed and parts can be ordered quickly so I am not left without a car for any longer than I have to be.
 
Upvote 0
I just took my 2016 GT into the dealership for a coolant leak in the rear of the engine today (4/10/2021). I purchased the car used in 2019 with an extended warranty. My dealer has not been able to locate the source of the leak after using a scope and running a pressure test. After reading the threads on here about the 2016 CX-9 coolant leak problems, it's seeming like I will need an engine replacement as well. The last update we got was they were not wanting to disassemble around where the leak is coming from because the warranty will not fully cover the labor required to do that, which is 3-4 hours. My dealer will not give a loaner car or rental car until the leak is diagnosed so now I am left without a vehicle until that happens. Hoping that the issue can be diagnosed and parts can be ordered quickly so I am not left without a car for any longer than I have to be.
How many miles?
 
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I have a 2018 mazda cx9 gt, 68,000 miles. Never had a prob, well maintained, love this car.......went to family up in ohio, 500 mile trip one way. We were up there a week and evening before heading home, i noticed puddle under car and figured it was ac condensate, although i must have sensed puddle was too far to center of vehicle......i dont know why i checked, but it was coolant. I couldnt believe it. Coolant leak was dripping off splashshield under car at oil pan access cover. Checked overflow resevoir and it was really low. Went down to local autozone and purchased fl-22 asian green coolant and topped coolant off to correct levels. I jacked up car and removed access panel. Coolant droplets everywhere around area and i could tell leak was coming from above, back side of engine. Couldnt see up that far with exhaust, turbo, etc. in the way.tight up there! Car never got hot and runs/idles perfect. Oil was changed just before the trip and looked great. Long story short , i drove it home the next day after local dealership wanted 5 days before he could even look at it, even after my vacation trip nightmare story(yes, i will share my story with Mazda and their dealership shotcomings when i get through this mess) Drove it home next morning...70 to 80, even using ac at times, watching the coolant temp and it ran perfectly all the way home. I called dealer that afternoon when we got home and he said to bring it in next morning. I brought it in the next morning and that afternoon they called me and stated it was a cracked head. I have an extended warranty for 8 years, 125,000 miles i originally purchased with the brand new vehicle. Service rep told me Mazda wanted block changed too and was going back and forth with warranty rep. Extended warranty wanted to inspect and 3rd party inspector will have looked at it it by end of Monday so we will see how it goes. I have purchased 4 new mazdas in the last 12 years and am a bit shocked by this problem. Glad i got it home without incident, but has been a painful experience and i hope this ends well. I have been looking at the competition for the cx9 on line all weekend and you know, i just dont see anything out there that checks all the boxes for my needs like the cx9. Monday i should know more and will report....
 
Upvote 0
I have a 2018 mazda cx9 gt, 68,000 miles. Never had a prob, well maintained, love this car.......went to family up in ohio, 500 mile trip one way. We were up there a week and evening before heading home, i noticed puddle under car and figured it was ac condensate, although i must have sensed puddle was too far to center of vehicle......i dont know why i checked, but it was coolant. I couldnt believe it. Coolant leak was dripping off splashshield under car at oil pan access cover. Checked overflow resevoir and it was really low. Went down to local autozone and purchased fl-22 asian green coolant and topped coolant off to correct levels. I jacked up car and removed access panel. Coolant droplets everywhere around area and i could tell leak was coming from above, back side of engine. Couldnt see up that far with exhaust, turbo, etc. in the way.tight up there! Car never got hot and runs/idles perfect. Oil was changed just before the trip and looked great. Long story short , i drove it home the next day after local dealership wanted 5 days before he could even look at it, even after my vacation trip nightmare story(yes, i will share my story with Mazda and their dealership shotcomings when i get through this mess) Drove it home next morning...70 to 80, even using ac at times, watching the coolant temp and it ran perfectly all the way home. I called dealer that afternoon when we got home and he said to bring it in next morning. I brought it in the next morning and that afternoon they called me and stated it was a cracked head. I have an extended warranty for 8 years, 125,000 miles i originally purchased with the brand new vehicle. Service rep told me Mazda wanted block changed too and was going back and forth with warranty rep. Extended warranty wanted to inspect and 3rd party inspector will have looked at it it by end of Monday so we will see how it goes. I have purchased 4 new mazdas in the last 12 years and am a bit shocked by this problem. Glad i got it home without incident, but has been a painful experience and i hope this ends well. I have been looking at the competition for the cx9 on line all weekend and you know, i just dont see anything out there that checks all the boxes for my needs like the cx9. Monday i should know more and will report....
This sounds exactly like whats going on in my 2016, it’s leaking from the exact same spot. We filled it with coolant last night to get to the dealer today and this morning almost half of it was on my garage floor. I really hope the warranty company and my dealership don’t give us the runaround and get the repairs/replacement done ASAP. We have also kept the car very well maintained and really love it. This is the first major issue we have ever had.
 
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