Poll 2.5T Coolant Leak/Engine Replacement

Who is having coolant leak issues and have had their engines replaced?

  • Yes

    Votes: 22 34.4%
  • No

    Votes: 42 65.6%

  • Total voters
    64

sm1ke

Work In Progress..
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Canada
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'18 CX-9 Signature
Thanks for putting this form together. It will be interesting to see the results.

I just got off the phone with Mazda USA regarding our 2016 and after a 3 month wait for a new engine, they have escalated it to the top level and will be flying the part from Japan as soon as they can coordinate it. They will be updating me with an ETA in the next couple of days.

In my last conversation with the dealer, they let me know that there is another CX9 waiting behind mine for a new engine now.

The Mazda USA rep was extremely professional and really seemed to want to help. He is confirming for me whether the new parts are updated from the original. I suspect they are, but let's see what I hear back.

Thanks for providing this update! Very much appreciated.
 

far4ngn

2016 CX-9 GT
I just received confirmation that the new parts are redesigned. This includes the head and exhaust manifold gasket. The combination is reported to reduce the overall force on the head. The change is reported to have happened 6 months ago, so I guess that means that the problem exists right through at least part of the 2021 model run.
 
I just received confirmation that the new parts are redesigned. This includes the head and exhaust manifold gasket. The combination is reported to reduce the overall force on the head. The change is reported to have happened 6 months ago, so I guess that means that the problem exists right through at least part of the 2021 model run.
Holy cow. I'm glad I didn't take them up on trading in for a '21....
 
I just received confirmation that the new parts are redesigned. This includes the head and exhaust manifold gasket. The combination is reported to reduce the overall force on the head. The change is reported to have happened 6 months ago, so I guess that means that the problem exists right through at least part of the 2021 model run.
So, I wonder if the choice of octane and the related effect that has on timing, would affect cylinder pressure enough to make any difference..??
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
Dang!! My 2020 is destined to fail. F*@k!!

Let's not jump to conclusions. It's something to be mindful of, for sure, but not every owner is going to experience this issue. Plus, now that we're aware that there are new parts that are expected to resolve the issue, we can be hopeful that a TSB will arrive as a result, which will potentially be helpful in getting some support should this issue occur in earlier MYs, even if they are out of warranty. Not to say that all engines out of warranty will be covered as a result of the TSB, but having that info out there can only help those people make their case.
 
Let's not jump to conclusions. It's something to be mindful of, for sure, but not every owner is going to experience this issue. Plus, now that we're aware that there are new parts that are expected to resolve the issue, we can be hopeful that a TSB will arrive as a result, which will potentially be helpful in getting some support should this issue occur in earlier MYs, even if they are out of warranty. Not to say that all engines out of warranty will be covered as a result of the TSB, but having that info out there can only help those people make their case.
It's just my luck that worries me.... ..Been on the wrong side through out my life.
 
So, I wonder if the choice of octane and the related effect that has on timing, would affect cylinder pressure enough to make any difference..??
I'm going to say likely not. I ran 92/93 octane for the entire time I've owned my CX-9, unless you're implying that running 87 octane would be better?
 

far4ngn

2016 CX-9 GT
I'm going to say likely not. I ran 92/93 octane for the entire time I've owned my CX-9, unless you're implying that running 87 octane would be better?
I agree on octane not being a likely contributor. I have run 87 octane 90% of the time. It's hard to say what the frequency of failure is at this point, but I would suspect it's well under 10% and may even be in the low single digits. My CX9 is a '16 and has 90k on it, so it is likely in a small group of 2.5t engines that have covered that higher mileage at this point.
 
I'm going to say likely not. I ran 92/93 octane for the entire time I've owned my CX-9, unless you're implying that running 87 octane would be better?
My thought is that possibly 87 octane being used, would therefore cause the ECM to adjust timing to be more retarded than 93 octane..
Therefore if I understand the cause and affect that various aspects have on cylinder pressure correctly, then the lower octane/timing would equate to lower cylinder pressure verses higher octane and the correlated more advanced timing.
Please pardon my inability to phrase that better at this moment in time.
So to take it a step further, I wonder if the revised head gasket is also a little bit thicker in order to lower cylinder pressure..??
And if a thicker head gasket, what minor affect does that have on horsepower/torque?
As for the exhaust manifold gasket revision, I have no idea how that helps...
Unless it somehow results in better flow..??
I'm just curious more than anything and welcome discussion on the matter from all of us interested on this forum.. ..Being we are not currently given by Mazda a complete explanation on the matter.
I also wonder if the suggestion by another poster of re-torquing the head bolts would be of any benefit.
 
I agree on octane not being a likely contributor. I have run 87 octane 90% of the time. It's hard to say what the frequency of failure is at this point, but I would suspect it's well under 10% and may even be in the low single digits. My CX9 is a '16 and has 90k on it, so it is likely in a small group of 2.5t engines that have covered that higher mileage at this point.
Well, with your experience it doesn't make the case that the lower octane prevents this issue, but it did last longer than s0n1c's 2018 with 40K running 92-93 octane.
Like I said, this doesn't make a solid case for low octane being less damaging on these engines to the point of being dogmatic.. But I do think that the lower octane/timing has at least some affect on cylinder pressure.
 
:
2010 CX-9 GT
The peak torque occurs at about 2k RPM and is not impacted by reduced octane. This theory doesn't bear scrutiny.
 
:
2018 CX-9 GT
The peak torque occurs at about 2k RPM and is not impacted by reduced octane. This theory doesn't bear scrutiny.

I agree with jal142. The most strain on an engine is when it delivers its maximum torque. The higher octane allows more torque at the end of the powerband, but at that point the torque is still a fair bit lower than what is achievable at 2000 rpm with 87 octane.
 
Well, with your experience it doesn't make the case that the lower octane prevents this issue, but it did last longer than s0n1c's 2018 with 40K running 92-93 octane.
Like I said, this doesn't make a solid case for low octane being less damaging on these engines to the point of being dogmatic.. But I do think that the lower octane/timing has at least some affect on cylinder pressure.
I can add some data to this....my 2018 cx9 had the issue at 68,000 miles....i have always used premium since i purchased new. We need more details, facts from Mazda.
 
The peak torque occurs at about 2k RPM and is not impacted by reduced octane. This theory doesn't bear scrutiny.
With regular fuel, the 2.5L turbo-four produces 227 horsepower and 310 lb-ft of torque. If you use premium fuel, those numbers go up to 250 horsepower and 320 lb-ft of torque.
 
Maybe we can add an octane used field to this form. I really don’t think it should be a factor, but who knows.....
I think it would be well worth having that data. This would then easily prove my idea wrong once we receive data to the contrary.
 
At this point, I'm highly considering using 87 Top Tier Gas from Costco rather than the 93 I've been using so far. My vehicle was a COVID opportunity back in May 2020 and just purchased it because I had a hunch that inflation would bite me in the future on a new car purchase. That said; I don't have hardly any miles racked up to be a contender in this at this point. However I do tend to keep vehicles for a very long time.
 
:
2010 CX-9 GT
With regular fuel, the 2.5L turbo-four produces 227 horsepower and 310 lb-ft of torque. If you use premium fuel, those numbers go up to 250 horsepower and 320 lb-ft of torque.

In 2018 and newer vehicles this is true. However, this is incorrect for the 2016 and 2017 models, which made 310 regardless of octane.