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.
I got word from Mazda yesterday that the engine should be arriving Tuesday and I should have my Cx9 back this week. Hopefully everyone else is having some luck.

I’m going on 24 days with it at the dealer.
 
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Thats great news! Wed June 2 will be 2 months that mine has been at the dealer. No word on when the engine is coming in...I do have the cx5 loaner, but really do miss the cx9.
 
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Thats great news! Wed June 2 will be 2 months that mine has been at the dealer. No word on when the engine is coming in...I do have the cx5 loaner, but really do miss the cx9.
Oh damn. Have you asked them for any updates? I got an updated text and email from the dealer like I do when I go for service and I messaged the advisor. She responded quickly giving me the updates.
 
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I called my service rep a few weeks ago and he said he could install the engine in a couple of days once it came in...but he didnt know when that would be. I will call him midweek. Let us know how it goes with yours!
 
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Finally have some good news (hopefully)!! My dealer said in their system it says the new engines ship date is 6/9/21🎉. After not having my car for roughly 9 weeks, this is a huge step in the right direction. The good news is, after not having the car for this long means when I get it back it’ll be just like getting a new car.
 
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pitkact

Member
:
CX-9
Well, I'm next. 2016 CX-9, 65k miles. started idling rough, then it started overheating. Then I got a check engine light. Added more coolant, temp didn't drop. After the car restart, got a lot of white smoke. Towing it to the dealer tomorrow. Wish me luck. Hoping mazda will cover it. (I already had the transmission replaced at 55k miles).
 
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JPL

:
2018 Mazda6, CX-9
Well, I'm next. 2016 CX-9, 65k miles. started idling rough, then it started overheating. Then I got a check engine light. Added more coolant, temp didn't drop. After the car restart, got a lot of white smoke. Towing it to the dealer tomorrow. Wish me luck. Hoping mazda will cover it. (I already had the transmission replaced at 55k miles).
Transmission replaced too? Surprising. The 6-speed is known to be very reliable.

Hope Mazda takes care of you. No extended warranty? 5K after standard powertrain. That would be tough to swallow if they don't cover it.
 
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sm1ke

Work In Progress..
Moderator
Contributor
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Canada
:
'18 CX-9 Signature
Well, I'm next. 2016 CX-9, 65k miles. started idling rough, then it started overheating. Then I got a check engine light. Added more coolant, temp didn't drop. After the car restart, got a lot of white smoke. Towing it to the dealer tomorrow. Wish me luck. Hoping mazda will cover it. (I already had the transmission replaced at 55k miles).

That's the first I've heard of a transmission failure. Did all of the above happen in the same drive? Or did it gradually progress?
 
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pitkact

Member
:
CX-9
That's the first I've heard of a transmission failure. Did all of the above happen in the same drive? Or did it gradually progress?
transmission started slipping. They replaced it. it was still under warranty.
all of the above happened in one drive. Left work, started the car... rough idle. But it was driving ok. Got off the highway, temp started to rise when I was stopped at the traffic lights. I was by Autozone so, I checked the coolant - it was gone. I added some more, temps didn't go down, still overheating.( temps were normal when driving, rising quickly when stopped). I drove to a friend's shop. I shut off the car. when he started it 10-15 minutes later, white smoke of death came out of the exhaust lol. So we towed it to the dealer. The dealer called today - they'll just need to confirm the issue and will call Mazda to see if they'll cover it out of warranty. He said it's a super common issue and Mazda is aware of it.
 
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pitkact

Member
:
CX-9
Transmission replaced too? Surprising. The 6-speed is known to be very reliable.

Hope Mazda takes care of you. No extended warranty? 5K after standard powertrain. That would be tough to swallow if they don't cover it.
I've had other Japanese cars before. never had any major issues. My first Mazda, and the experience is less than ideal lol. Whether they'll cover it or not, it looks like I'll be selling it and saying bye to Mazda. If they'll replace the engine, there's a pretty good chance, the same thing will happen in 40-50k miles again. I love how it drives, but I need something a bit more reliable.
 
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Anyone knows where the leak goes to? My 2020 CX-9 FWD certainly have leak and it is only 6k km. During my last visit to dealer for 6 months maintenance I have ask them to refill the coolant. And I have checked as well once the work done that the coolant level is slightly below F indicator. Tomorrow in the morning, the coolant level is already near E indicator. I check below the car it is dry. I check the dipstick it is normal as well. Really confusing. So far every time I drive the car engine temp is 84-86°C which I assume normal because it is like that from the first time I drive the car.
 
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Winnipeg Canada
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2017 CX-9 GT
I've had other Japanese cars before. never had any major issues. My first Mazda, and the experience is less than ideal lol. Whether they'll cover it or not, it looks like I'll be selling it and saying bye to Mazda. If they'll replace the engine, there's a pretty good chance, the same thing will happen in 40-50k miles again. I love how it drives, but I need something a bit more reliable.
I understand what you mean about not trusting the replacement engine any more than the original. But that's something to bring up with the dealer. In fact, we're all wondering the same thing. If you can, ask them if they know what years are affected and also were there changes made to the engines that are being swapped in to eliminate this issue. It would be interesting to see what they say. And good luck!
 
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Winnipeg Canada
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2017 CX-9 GT
Anyone knows where the leak goes to? My 2020 CX-9 FWD certainly have leak and it is only 6k km. During my last visit to dealer for 6 months maintenance I have ask them to refill the coolant. And I have checked as well once the work done that the coolant level is slightly below F indicator. Tomorrow in the morning, the coolant level is already near E indicator. I check below the car it is dry. I check the dipstick it is normal as well. Really confusing. So far every time I drive the car engine temp is 84-86°C which I assume normal because it is like that from the first time I drive the car.
It could be a broken head gasket. This would allow the coolant to leak into other parts of the engine including the combustion chamber. Check your oil, it's probably got coolant in it.
 
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sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
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'18 CX-9 Signature
I've had other Japanese cars before. never had any major issues. My first Mazda, and the experience is less than ideal lol. Whether they'll cover it or not, it looks like I'll be selling it and saying bye to Mazda. If they'll replace the engine, there's a pretty good chance, the same thing will happen in 40-50k miles again. I love how it drives, but I need something a bit more reliable.

I don't know about that, but as Glaucus mentioned, it can be hard to trust a replacement engine without knowing what went wrong and whether the new engine addresses the issue. Sorry to hear, but at least right now is a great time to be selling a vehicle.


Anyone knows where the leak goes to? My 2020 CX-9 FWD certainly have leak and it is only 6k km. During my last visit to dealer for 6 months maintenance I have ask them to refill the coolant. And I have checked as well once the work done that the coolant level is slightly below F indicator. Tomorrow in the morning, the coolant level is already near E indicator. I check below the car it is dry. I check the dipstick it is normal as well. Really confusing. So far every time I drive the car engine temp is 84-86°C which I assume normal because it is like that from the first time I drive the car.

Typically it seems to leak on the back side of the engine. Keep in mind that coolant level will fluctuate depending on when you check it. If the engine it hot, the level will be higher, and if the engine is cold, it will be lower. To monitor for leaks, check the engine at a consistent time (meaning always when the engine has been sitting overnight, or always after a 10 minute drive).
 
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JPL

:
2018 Mazda6, CX-9
I've had other Japanese cars before. never had any major issues. My first Mazda, and the experience is less than ideal lol. Whether they'll cover it or not, it looks like I'll be selling it and saying bye to Mazda. If they'll replace the engine, there's a pretty good chance, the same thing will happen in 40-50k miles again. I love how it drives, but I need something a bit more reliable.
I understand your disappointment. Even with this issue, Mazda is the #1 most reliable brand (Consumer Reports). Go figure.
 
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It could be a broken head gasket. This would allow the coolant to leak into other parts of the engine including the combustion chamber. Check your oil, it's probably got coolant in it.
I have checked it and the oil level is normal between the two dots hole.
 
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I don't know about that, but as Glaucus mentioned, it can be hard to trust a replacement engine without knowing what went wrong and whether the new engine addresses the issue. Sorry to hear, but at least right now is a great time to be selling a vehicle.




Typically it seems to leak on the back side of the engine. Keep in mind that coolant level will fluctuate depending on when you check it. If the engine it hot, the level will be higher, and if the engine is cold, it will be lower. To monitor for leaks, check the engine at a consistent time (meaning always when the engine has been sitting overnight, or always after a 10 minute drive).
Is the difference that much between cold and hot engine? I mean if the coolant in reservoir can go from almost full to almost empty, there must be some leaks right? It just that it is quite confusing that when I checked the floor it is dry and there is no increase in oil level.
 
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Is the difference that much between cold and hot engine? I mean if the coolant in reservoir can go from almost full to almost empty, there must be some leaks right? It just that it is quite confusing that when I checked the floor it is dry and there is no increase in oil level.
There can be quite a difference. As @sm1ke said, check it at the same time, at the same heat every time. If you are leaking into the cylinder, you wouldn’t have any coolant on the ground as it would be burning and sent out the exhaust. My car right before this was leaking into the cylinder. There was a slightly fruity smell every time I parked it in the garage and I had to top off coolant about once every other week. No pools on the ground when it was parked
 
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sm1ke

Work In Progress..
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Canada
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'18 CX-9 Signature
Is the difference that much between cold and hot engine? I mean if the coolant in reservoir can go from almost full to almost empty, there must be some leaks right? It just that it is quite confusing that when I checked the floor it is dry and there is no increase in oil level.

On my car, when the reservoir level is checked after I get to work (hot engine), it's right below the top of the "F". If I check it around noon (cool engine, about 5 hours later), the level is about an inch and a half below the full mark.
 
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