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.

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
I don’t know that’s true. There’s a specific “manufactured before” date on the TSP, which implies they had a point where something changed. Maybe I’m overthinking it, but given how long some of these issues took to develop, I’m not sure they can validate any of their changes corrected the problem.
In addition to specific “produced before Jun. 9, 2020” for CX-5 and CX-9、”produced before Mar. 25, 2020” for Mazda6 on the TSB, it also says “the design of the exhaust manifold gasket and the cylinder head has been modified to reduce the force on the cylinder head.” This means there were design changes and those changes had been introduced into the assembly line on these dates.

The only thing for the 2.5T now is whether or not these changes are effective to stop the head crack in the long run. Only time will tell.
 
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dynamho

Member
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02Protege 06RX8
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17M6GT 21CX5sig
Mazda recently put out this TSB for coolant leak because of cracks in the cylinder head.
As reported by many here it seems to affect the 2.5T 2016-2020 CX-9 as well as 2019-2020 CX-5 and 2018-2020 Mazda6
So all the initial 2.5T production model iterations.

Notice that CX-30 and Mazda3 2.5T are spared. Perhaps the cylinder head to exhaust design is significantly different in the newer models.

Looks like Mazda was observing the issue and made design/production changes for all 2021 models.
 
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2016 CX-9
This is my first Mazda. It seems to be well put together. I’ve kept it very well maintained. Sadly, it seems like we are experiencing the same issue.

I’m confident Mazda will live up to their Brand reputation. I’ll keep posted.
 
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This is my first Mazda. It seems to be well put together. I’ve kept it very well maintained. Sadly, it seems like we are experiencing the same issue.

I’m confident Mazda will live up to their Brand reputation. I’ll keep posted.
I agree with you about it being well put together. My 3-year-old (actually 4, since it was assembled in late 2017) CX-9 is better assembled and tighter than 95% of the cars I test drove when looking to replace it (I could write a thorough car-and-driver-like post about it at this point). Back on topic here: How long ago was your issue found?
 
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2016 CX-9
I agree with you about it being well put together. My 3-year-old (actually 4, since it was assembled in late 2017) CX-9 is better assembled and tighter than 95% of the cars I test drove when looking to replace it (I could write a thorough car-and-driver-like post about it at this point). Back on topic here: How long ago was your issue found?
The dealer said, based on what he discovered it’s been going on for a while. However, it never ran hot. I constantly watch my needles. Still, apparently the dealer discovered it this most recent visit.
 
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2010 CX-9 GT
This is my first Mazda. It seems to be well put together. I’ve kept it very well maintained. Sadly, it seems like we are experiencing the same issue.

I’m confident Mazda will live up to their Brand reputation. I’ll keep posted.

Well assembled with a poorly designed engine. Hopefully the new head fixes it.
 
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Mazda CX-9 Grand Touring 2016
The dealer said, based on what he discovered it’s been going on for a while. However, it never ran hot. I constantly watch my needles. Still, apparently the dealer discovered it this most recent visit.
It would run hot if so much coolant leaked out to the point where the cooling system inside the engine was low. More damaging would be coolant leaking into the oil and the bearing failing due to the contaminated oil.

Check the appearance of the oil on your dipstick. If it is at all milky, get the oil changed right now.
 
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Winnipeg Canada
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2017 CX-9 GT
Interesting. So bumps could cause the issue. Great.

So does this TSB mean Mazda is committing to fixing these issues as they arise even after warranty?
 
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sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
Interesting. So bumps could cause the issue. Great.

So does this TSB mean Mazda is committing to fixing these issues as they arise even after warranty?

Right? It's okay though, everyone's roads are perfectly smooth, especially ours. :rolleyes: 😅

I'm not sure if they'll fix them out of warranty yet. I should hope so, but we'll have to wait and see how the 2016 MY owners are treated as they come out of warranty and go from there.
 
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Winnipeg Canada
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2017 CX-9 GT
Right? It's okay though, everyone's roads are perfectly smooth, especially ours. :rolleyes: 😅

I'm not sure if they'll fix them out of warranty yet. I should hope so, but we'll have to wait and see how the 2016 MY owners are treated as they come out of warranty and go from there.
Ya, if bumps were the main culprit, mine would blown years ago! :D

Well, the TSB pretty much admits it's a design/manufacturing flaw. That gives us some leverage. Maybe I'm wrong, but I believe there have been some reports of customers having it fixed out of warranty, so perhaps they just feel it's gonna be a rare issue and they'll fix them as they arise.
 
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sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
Ya, if bumps were the main culprit, mine would blown years ago! :D

Well, the TSB pretty much admits it's a design/manufacturing flaw. That gives us some leverage. Maybe I'm wrong, but I believe there have been some reports of customers having it fixed out of warranty, so perhaps they just feel it's gonna be a rare issue and they'll fix them as they arise.

Is yours a locally owned vehicle, or was it brought in from another province?

I think I remember at least one 2nd gen owner who was able to get the engine replaced on Mazda's dime while they were out of warranty.
 
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Winnipeg Canada
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2017 CX-9 GT
Is yours a locally owned vehicle, or was it brought in from another province?

I think I remember at least one 2nd gen owner who was able to get the engine replaced on Mazda's dime while they were out of warranty.
Mine was originally from Saskatchewan. I hope that doesn't make a difference. I've taken it to Gerry Gordon's Mazda a few times now for oil changes and other services mostly to get acquainted. I find it's best to build a relationship before you ask for free stuff. :) My warranty ends in February, so I'll probably go for an early oil change in January and have them inspect the thing thoroughly.
 
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sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
Mine was originally from Saskatchewan. I hope that doesn't make a difference. I've taken it to Gerry Gordon's Mazda a few times now for oil changes and other services mostly to get acquainted. I find it's best to build a relationship before you ask for free stuff. :) My warranty ends in February, so I'll probably go for an early oil change in January and have them inspect the thing thoroughly.

Nah I don't think it'll make a difference, I was just curious. I've taken my car to Crown Mazda and Gerry Gordon's, and GG seems to be the better of the two from a customer service perspective. Josh and Leesa at the service desk have been pretty great.
 
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Winnipeg Canada
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2017 CX-9 GT
Nah I don't think it'll make a difference, I was just curious.

Speaking of bumps and Saskatchewan... we went to Banff and Drumheller this summer. On the way back we were gonna stop at the in-laws which are by Russel MB. So from Drumheller there's a straight line between #1 and #16 Hwys, so I figured that would be the shortest, fastest way. It turns out we took the worst road in the universe. In fact, not sure how they even call it a road. If the car survived that abuse for I can't remember how many hours, I think I'm good! Not only was that road barely driveable at any speed, I had to pull over more than once to let combines pass and even a full house that was being towed down the road. Unreal experience that was. Once we crossed into MB we hit freshly paved road.

Anyway, sorry to take it off topic like that, but something just jarred my memory there....
 
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yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
I missed where bumps are mentioned that may be causing the issue?
Right in the TSB 01-013/21 Coolant Leaks at Cylinder Head Hawke posted earlier:

“DESCRIPTION

Some vehicles may have coolant leaks at the cylinder head around the exhaust manifold (as shown below). There may be cracks at the stud bolt hole (1) or at the outside of the exhaust manifold (2).

Cracks may be caused by:
• Deformation of the exhaust manifold during usage causing unexpected force to certain areas of the cylinder head.
• Residual stress generated during production in the cylinder head material may be greater than expected. The
external force from the exhaust system when driving over bumps may cause unexpected force to certain areas of the cylinder head.


To eliminate this concern, the design of the exhaust manifold gasket and the cylinder head has been modified to reduce the force on the cylinder head.
 
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Winnipeg Canada
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2017 CX-9 GT
You'd think they could design a support bracket they could install to help reduce the load on the cylinder head.
 
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yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
You'd think they could design a support bracket they could install to help reduce the load on the cylinder head.
IMO there’re more into this problem. The cylinder head on the 2.5T is revised from the 2.5L NA but the crack happens only on the 2.5T. I remember some people also mentioned the cracks are found on the cylinder block hence the engine replacement.
 
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