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
:
2016 CX-9 GT
I agree that it is too early to press the panic button. As far as stats goes however, i wouldn’t include models years past 2018 for a good representation. The 2019 and younger are unlikely to have enough mileage on them for this issue to come up in significant numbers. Plus the pandemic in my opinion is slowing the down the rate of issues. I wish i would be driving my 2018 more (like I usually do) so that normal issues would come while still under the initial warranty. At this rate of driving, items normally dealt with under warranty will break a year or two later when I am out of it.
Fair enough. Taking just 2016-2018 brings the total down to 69,681 sold. Assuming 2000 engines still, that’s only 2.9%. Doubling that is close to 6% which is for sure more alarming than 1.3%, but you are still far more likely to have a fine engine than one that needs to be replaced. I still think that FB guy is full of crap. I would also be interested to see why engines are failing. IF there are 1000 coming to the US, how many of those are due to poor maintenance? I have met far too many people that don’t know their oil change intervals and ignore the maintenance reminders. I don’t think we can assume that every replacement engine was due to manufacturer defect
 
:
2016 CX-9 GT
He's not. He's having his engine replace due to this coolant issue.
Great. Does he work for Mazda? Where did he come up with 1000 engines waiting to be replaced? Unless somebody from Mazda can confirm the number, it’s just a rumor.
 
Ouch, scary stories. I got my 2017 sport just a month back. Car fax didnt share much info, but it had 2 previous owners. Is there an easy way to check if the engine was replaced? Is it easy to find some engine serial number or something. If it never was, I hope the 7 year warranty covers it. Just curious, how much can the replacement cost be outside warranty?
 
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2010 CX-9 GT
Fair enough. Taking just 2016-2018 brings the total down to 69,681 sold. Assuming 2000 engines still, that’s only 2.9%. Doubling that is close to 6% which is for sure more alarming than 1.3%, but you are still far more likely to have a fine engine than one that needs to be replaced. I still think that FB guy is full of crap. I would also be interested to see why engines are failing. IF there are 1000 coming to the US, how many of those are due to poor maintenance? I have met far too many people that don’t know their oil change intervals and ignore the maintenance reminders. I don’t think we can assume that every replacement engine was due to manufacturer defect

Poor maintenance doesn't lead to a cracked cylinder head. Let's be reasonable. This is a design issue or manufacturing defect. If it's a design issue, everyone with this engine has something to worry about. Hopefully, it is a manufacturing process control issue that only impacted a limited number of cars.

It would be really nice if Mazda stepped up and officially acknowledged the issue and extended the engine warranty. Otherwise, one could assume that the goodwill engine replacements will come to an end at some future, unannounced, date.
 

sm1ke

Work In Progress..
Moderator
Contributor
:
Canada
:
'18 CX-9 Signature
I think @MGMGT16 is just saying that a 2016+ CX-9 engine replacement may not always be due to a coolant leak. If the statement that "1000 engines are coming to the US" is true, we don't know if all of those engines are for customers experiencing coolant leak issues. They may be warehouse inventory, replacements for poorly maintained engines (seized engine due to oil sludge), replacements for engines damaged by excessive oil dilution, and/or replacements for engines that have the coolant leak issue.

As @jal142 mentioned, hopefully this is just a manufacturing/assembly defect of some sort.
 
:
Winnipeg Canada
:
2017 CX-9 GT
I agree, we're not sure if those are all 2.5 Turbo engines or exclusively for the CX-9. What I have heard is people waiting months for one, so that kinda jives.
 
Last edited:
:
Winnipeg Canada
:
2017 CX-9 GT
Btw, reading further down the comments, that guy who posted above is also waiting for a transmission as well. Apparently a few people on the FB group have made the same complaint. Weird, never heard of that before, but it can happen. That guy has some really bad luck though! :oops:
 
:
2016 CX-9 GT
I think @MGMGT16 is just saying that a 2016+ CX-9 engine replacement may not always be due to a coolant leak. If the statement that "1000 engines are coming to the US" is true, we don't know if all of those engines are for customers experiencing coolant leak issues. They may be warehouse inventory, replacements for poorly maintained engines (seized engine due to oil sludge), replacements for engines damaged by excessive oil dilution, and/or replacements for engines that have the coolant leak issue.
Spot on. Statement from the FB guy is not specific about why or where the “1000 engines” are heading nor does it cite any credible sources. Just approach their statement with a healthy amount of skepticism. It’s very narrow minded to assume, if the 1000 engines exist, that they are all for this coolant leak.
 

JPL

:
2018 Mazda6, CX-9
The other variant could relate to driving style. Clearly, this relates to engine stress. Does a CX-9 that's been driven more aggressively and under boost a lot more often a possible causation? Not talking about thrashing the car near redline all the time but just that the CX-9 does need it's available power often for quick merging and passing.

So maybe a question could be...does anyone here getting a replacement drive like an old lady and still got the coolant leak?
 
I took really good care of mine and would blast it here and there, but never excessively. It's definitely a design flaw. Currently, with the new engine, it has never run this strong. I just hope problem is eliminated and cannot happen again.
 
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:
2010 CX-9 GT
Cracking issues are usually related to heat cycling. There were posts here that identified the cracks as starting near or at the exhaust manifold studs in the head. This area of the engine gets really hot very quickly when the engine starts and runs, then it cools down back to ambient when the engine shuts off.

In a modern engine the exhaust gas temperature can get very hot even when not beating on the engine. The ECU is constantly trying to get to stoichiometric air/fuel ratio due to emissions concerns. This is nearly the hottest flame temperature. The head will get hotter with sustained full throttle runs, but this issue is probably going to happen just with normal use as the head builds up hot/cold cycles from ambient to normal operating temperature.

Plus, I recall reading somewhere that Mazda purposefully designed the engine to run the head a little hotter than they previously did on other designs to help with carbon build up on the valves. I wonder if this bit them in the ass.
 
:
2019 CX-9 Signature
The best news so far was the member who posted the new engine part# matched the 2019+ part# and was said that it fixed the issue.
 
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Winnipeg Canada
:
2017 CX-9 GT
Ya, I often wonder if people blowing engines are towing stuff around in an area with mountains. You never know.

But ya, excessive heat is the #1 suspect. I wonder if simply removing the superfluous engine cover might help?
 

trussrules

Member
:
09 Mazda5 Touring
2017 GT with 36k miles. Had 30k service done in April at the dealer with no issues. Drove cross country last week to move (2200 mile trip) and about halfway through smelled coolant when filling up with gas. Checked and the reservoir was empty and noticed some drips under the car. Added some coolant and finished the trip with no issues. Car drove fine.

A couple of days ago sitting in traffic the temp light came on. Pulled over and saw the coolant tank empty again. Took it to the dealer. Service advisor said the leak was from the back of the engine and likely coming from a cylinder head. They were advised by Mazda to replace the engine. It is covered by the warranty but they don’t expect to get the replacement until the end of July.

Got my CX-9 back today - just shy of six weeks from when I dropped it off at the dealership. The Service Advisor said they found the coolant leak coming from the back of the block where the head meets the block, which he said was "due to improper casting."

It is a 2017 and they replaced it with part PYY7-02-300L, which is different than the part number that highfivezoom got - not sure what the difference is.

I'm a little nervous at the number of gaskets, seals, and o rings that were replaced - lots of possible points of failure, but only time will tell. So far it's driving great and I'm really happy to get it back. We had a 2021 CX-30 as a loaner and it's okay - but I missed having the bigger car.
 
:
2009 Mazda CX-9 GT
I'm a little nervous at the number of gaskets, seals, and o rings that were replaced - lots of possible points of failure, but only time will tell.
When you take apart an engine you must replace all the gaskets attached to what you are removing. This is normal.
 

pitkact

Member
:
CX-9
Im still waiting for my replacement. It’s been at the dealership since beginning of June. So 2.5 months now. They said they have few other to do ahead of mine, plus it takes a while to get engines.
 

JPL

:
2018 Mazda6, CX-9
Im still waiting for my replacement. It’s been at the dealership since beginning of June. So 2.5 months now. They said they have few other to do ahead of mine, plus it takes a while to get engines.
What arrangements are you guys getting in the meantime? Dealer loaner?

I'd likely trade for a new CX-9 if I wasn't provided a loaner at no cost for months. While also demanding full market value for trade since engine failure is Mazda's fault.
 
What arrangements are you guys getting in the meantime? Dealer loaner?

I'd likely trade for a new CX-9 if I wasn't provided a loaner at no cost for months. While also demanding full market value for trade since engine failure is Mazda's fault.
I've had a dealer loaner for over a month and a half so far lol
 
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