2.5T Engine Coolant Leaking TSB

They should install the revised head and exhaust gasket set so your car should be solid after the repair. I am curious if you get 16 new valves or if they reuse the original ones
The TSB is showing that the new set of valves is included with the cylinder head. But also many other gaskets in the turbocharger and water pump and fuel line and drive shaft, etc. Even the wheel alignment is listed among the things to do. Mazda is reimbursing 11.3 labor hours for this fix.
I will take the TSB to the dealer and ask that they do every single thing listed there and will also contact MazdaUSA for them to connect with the dealer and make sure everything is replaced since they will be paying the dealer for it.
Will follow up with more details.
 
Interesting info. You must have the maintenance manual procedure. I have the TSB and it just says head and exhaust gasket have been updated. Maybe you have a more recent revision then I have.
 

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is there any preventive measures that can be taken before the cylinder head cracks? has it been determined why some vehicles are affected or is it just a matter of time until all vehicles are affected?
 
is there any preventive measures that can be taken before the cylinder head cracks? has it been determined why some vehicles are affected or is it just a matter of time until all vehicles are affected?
I don't think there's anything you can do to prevent it. IMO it's a design flaw from the extra stress from the turbo.
 
is there any preventive measures that can be taken before the cylinder head cracks? has it been determined why some vehicles are affected or is it just a matter of time until all vehicles are affected?

I think the TSB states something along the lines of the exhaust system moving around too much when going over bumps, which causes unexpected forces that can cause the cylinder head to crack.

I have considered maybe replacing or reinforcing the exhaust system, or replacing the exhaust hangers with new ones, to prevent this from happening on my car, but I have no idea if it would help or not.
 
I want to say upstream of the cat is all bolted together with no flex. So if anything, a brace to relief the weight of the turbo off of the exhaust manifold might be something to look into.
 
They say it's aggravated by bumps so not off-roading and avoiding big pot holes may help you beat the odds.
 
@JPL

I’ve driven some forest service roads in WA state that are smooth and unjarring compared to the interstate and state HWYs.
 
They say it's aggravated by bumps so not off-roading and avoiding big pot holes may help you beat the odds.

We have some pretty bad roads here. Manageable, but I have hit quite a few potholes over the last 5 years. Same with my wife, who managed to hit one hard enough to cause a minor bend in one of the rims, and I've still been able to dodge the coolant leak issue for now.
 
is there any preventive measures that can be taken before the cylinder head cracks? has it been determined why some vehicles are affected or is it just a matter of time until all vehicles are affected?
The TSB says:

Cracks may be caused by:
• Expansion characteristics of the exhaust manifold during usage causing unexpected force to certain areas of the cylinder head.
• Residual stress generated during produbction 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.


So if you drive gently and always on the smooth road, you have less chance to make the cylinder head cracked.

It’s a design issue when Mazda modified the original SkyActiv cylinder head for the added turbo. It created certain weak areas which can’t stand the unexpected force like the original head hence cracked.
 
2019 Grand touring reserve with turbo engine - 24k miles. Never had any problems but engine temp overheated last weekend. Took into the mazda dealer and they are going to replace the cylinder head. Never noticed any coolant leaks or anything like that, but obviously seems related to the known issue with this model year and engine. Question for those who have experienced this: once they replace this cylinder head am I in the clear? Coming up on the end of my drivetrain warranty - glad it happened now I guess, but is this a sure fire fix or will I be dealing with other problems from this design flaw down the road?
 
2019 Grand touring reserve with turbo engine - 24k miles. Never had any problems but engine temp overheated last weekend. Took into the mazda dealer and they are going to replace the cylinder head. Never noticed any coolant leaks or anything like that, but obviously seems related to the known issue with this model year and engine. Question for those who have experienced this: once they replace this cylinder head am I in the clear? Coming up on the end of my drivetrain warranty - glad it happened now I guess, but is this a sure fire fix or will I be dealing with other problems from this design flaw down the road?
Mazda claimed they have revised the cylinder head and exhaust manifold gasket for this problem on the 2.5T. But only the time can tell if the revisions have actually fixed the problem for long term. It took 5 years to expose this cracked cylinder head problem from original head.

Personally I wouldn’t keep this 2.5T for too long as it’d cost an arm and a leg to fix if the same problem happens again without warranty.
 
2019 Grand touring reserve with turbo engine - 24k miles. Never had any problems but engine temp overheated last weekend. Took into the mazda dealer and they are going to replace the cylinder head. Never noticed any coolant leaks or anything like that, but obviously seems related to the known issue with this model year and engine. Question for those who have experienced this: once they replace this cylinder head am I in the clear? Coming up on the end of my drivetrain warranty - glad it happened now I guess, but is this a sure fire fix or will I be dealing with other problems from this design flaw down the road?
Thanks for sharing your experience. I also have a 2019 GT with almost identical mileage as yours and thus far haven't had any problem. From reading other posts here it appeared higher mileage vehicles were more prone to this problem but after seeing yours I'm wondering if that's a valid supposition? I buy a new car every 6 years, usually in March so I'm sweating out the next 20 months or so before I trade this SUV in.
 
All working well a month after the repair. The vehicle drives great.
I had the dealer do a firmware update of the TCM and the transmission shift learning reset.
OMG! The car drives like new. And I had both lower control arms replaced a few months ago.
I am in love again!
 
Yeah, by letting CX-9 owners waiting for 2 ~ 3 months, even getting the whole engine from Japan after repeated phone calls and complaints. That’s the quick turnaround replacing the whole engine?

Read these threads:

Poll 2.5T Coolant Leak/Engine Replacement. What can be done to prevent?

2016 CX-9 Signature leaking coolant

On those 2.5L with cylinder deactivation, Mazda started with replacing the entire engine when the CD is having problrms such as fallen rocker arm or failing HLAs. Later Mazda created a new part number on cylinder head with everything pre-installed for easy replacement on cylinder head, and Mazda no longer replaces the entire engine for the same CD issues. No, replacing cylinder head has to be more cost effective everything considered if the cylinder block itself has no issues.

So it isn’t just the cylinder head cracked like the TSB says. Cylinder block may also be the subject easy to crack too. That’s my suspicion.
How do you get Mazda corporate to fix the problem on the car ? Mine blew at 126K miles and I still owe $$ on the car. Any advice is appreciated
 
Hate to even say this but once they see 126k, conversation is over.
Conversation about good willing it or selling it? Honestly is appropriate for the situation I just don’t think it’s fair because I didn’t buy a car for it to fail 126k and I don’t think it’s right they just had to replace the transmission at 99k under a TSB and why not at-least make me aware of the issue
 
Conversation about good willing it or selling it? Honestly is appropriate for the situation I just don’t think it’s fair because I didn’t buy a car for it to fail 126k and I don’t think it’s right they just had to replace the transmission at 99k under a TSB and why not at-least make me aware of the issue
How many miles when you bought it?

A seller isn't going to tell you about a possible problem that may or may not happen. When they sold it to you it hadn't failed yet. While this is indeed a problem with the 2.5T, it isn't guaranteed to fail.

Unfortunately there's never going to be a goodwill repair on a vehicle over 100K. They have no obligation to help even though there's a design flaw. Technically, design flaws or manufacturing defects are only covered within the manufacturers warranty (the reason warranties even exist). 60,001 miles and you're out of luck.
 
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