NA CX-5 with Cylinder Deactivation Engine Repairs - Report In

A car manufacture won’t issue a TSB of SA unless there’re significant number of reports about the problem.

I can also argue that since very few of the CX-5 owners actually posting on this forum, there can be a lot more cases on this problem out there as they don’t post here.

Hyundai and KIA have issued a comical number of bulletins and recalls based on potential engine fires on previous models, with very few reports of actual fires. And that's only with issues related to engine fires, there's more unrelated to engine fires I think (too many from one manufacturer to keep track of). As far as I know, there is no ruleset for when a manufacturer issues a TSB or SA, it's up to their discretion.


I can also argue that since very few of the CX-5 owners actually posting on this forum, there can be a lot more cases on this problem out there as they don’t post here.

Agreed, but wouldn't you agree that if you had an issue, and you wanted to find a community that might have experience with the issue, you'd join an online forum or social media group? I understand that a good chunk of owners may not use forums or social media for various reasons, but a large majority of owners do.
 
Yes, there’re several reports here for cracked cylinder head on the 2.5L NA with CD. Those posts are mixed in those reports for the same problem on the 2.5T. Mazda started with the whole engine replacement; later changed to replace the cylinder head only at the dealership.
That's been said before but nobody can seem to produce an example. I think I might have seen one instance somewhere but I'm not certain. Again, out of probably 350,000+ units....
 
I think the TSB and service alert were released because of the potential safety risk when the issue is triggered (car goes into limp mode). I may be wrong, can someone confirm? Also important to know whether these issues are post-recall or not. With the limited reach our forum has, and the total number of issues reported, compared to actual sales of the 2018+ CX-5 with 2.5L NA engine, this issue seems to be very, very rare. Huge difference compared to the Honda CR-V and it's fuel dilution problems, for example.

The Facebook posts are where you tend to see most of the issues and I can't remember seeing a single thing on CD on a NA engine. Not a single thing. There are lot of posts on the oil burning issue but that we all know about. The whole CD issue was way overblown.
 
That's been said before but nobody can seem to produce an example. I think I might have seen one instance somewhere but I'm not certain. Again, out of probably 350,000+ units....
Yes and alot of these are occuring after the 60,000 mile warranty periods. As more of these 2018 and 2019 engines age between the 60 k and 100 k mark, there will be a much better snapshot overview of how many of these defects are failing prematurely.
 
The Facebook posts are where you tend to see most of the issues

This makes a lot of sense. With a Facebook group, posters likely already have a user account so they can skip the registration steps and jump straight into posting.
 
the Turbo oil burning is the most prevalen one I have seen. Then quite a few of the coolant leaking head issues on the Turbo as well.
Very rare ones for the CD. but you never know thats anecdotal. Only Mazda knows the real numbers.
To me if one wants to have problematic 200k+ , most likely pre 2017 models are better choice.
Too many innovations with the latest engines.
 
The Service Alert for a new CD cylinder head assembly (see attachment) may be conflated with cylinder head problems. Nowhere in the Service Alert is there an indication of a known problem being solved.

So why have a new head if there is no known problem with the old one? Maybe it shares some parts that proved problematic with the turbo and the CD version is along for the ride. Perhaps a material or part supplier was changed altering a specification in the process.

For example, you would have never known they changed valve seals in the turbo at some point if the replacements had not started failing while the originals evidently were not.

In general, in the worlds of tech and engineering, "if it ain't broke don't fix it" is never to be assumed. That expression is as old as God for a reason.

The fact the head was changed does raise unanswered questions and something to watch for. Until there are enough reports of failing heads in CDs you could just as well chalk up this new head assembly to good ol' Japanese continuous quality improvement...or some incremental cost cutting.
 

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  • New Cylinder Head Assembly.pdf
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Where are these reports? What will happen when a meaningful number get to 100,000 plus miles is just speculation.
Did you see my post earlier, post #13? That recent report, although it isn’t cracked cylinder head, with possible premature wear-and-tear problem on CD cylinder #4, is the problem I’ve been worried about all along on long-term reliability happening so often on every engine with cylinder deactivation. That’s why some car manufactures are alternating CD cylinders to average out the premature wear on those CD cylinders.

Both GM and Chrysler introduced their Displacement on Demand or Multi Displacement System when they brought out the early 2000s V8s.
Initially the same cylinders were being scored and damaged as were the cylinder linings so both companies were doing massive repairs out of pocket, so they reprogrammed the systems to make it random.
The impala SS, Grand Prix GTP, Charger, Challenger, I believe the NorthStar V8 as well as the 5.3 in the Tahoe/Yukon/Silverado/Sierra and possibly the 6.0 and I think the Corvettes also got that system.
Chrysler still has a problem with their MDS where it’s called the Hemi tick and flat spotting the cam shaft lobes and destroying the roller bearings.
Hopefully Mazda doesn’t get that bad, but I already asked a salesman at my local Mazda dealership I deal with if they have had any problems with the cylinder deactivation and what type of mileage customers are getting with it.
If there are no real problems than I would be ok with getting a CX5 with CD, but if Mazda has not randomized CD than I will stick with a CX5 2017 and older.
 
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Hyundai and KIA have issued a comical number of bulletins and recalls based on potential engine fires on previous models, with very few reports of actual fires. And that's only with issues related to engine fires, there's more unrelated to engine fires I think (too many from one manufacturer to keep track of). As far as I know, there is no ruleset for when a manufacturer issues a TSB or SA, it's up to their discretion.
You can’t mix safety recalls with TSBs and Service Alert. Very few engine fires may trigger a safety recall, but there has to be significant number of failures to prompt the car manufactures to issue a TSB or a SA.
 
There are a number of reports of cylinder head cracks on NA engines over at the mazdaforum.com site. It's a very long thread with a lot of extraneous commentary, so it's difficult to pin down just how many cases are documented, but it's definitely more than a couple.
Thanks for posting this. Over past several months, I have read several CX-5 non-turbo CD with head problems both on mazda247 forum and reddit but don't have time to research and post them all here to prove they exist.
I knew this was more widespread than some people say.
The Mazda forum thread was very useful.
Thanks again.
 
Here’s one long discussion:l in this forum:

Cracked Cylinder Head with Oil leaking...How common is this?

Some reports in another Mazda forum. Some complaints are at NHTSA website. And at least a thread at Reddit. Some happened with only 20K+ miles.
In that thread there’re 5 cases of cracked cylinder head on the 2.5L with CD, and 1 case on the 2.5T. A member waited 8 months for a new head to fix the engine.

I remember there’s another earlier thread with several reports of cracked cylinder head on the 2.5L with CD, and at the time Mazds was replacing the whole engine for the cracked head. Some even posted a couple of pictures which showed several removed engines suffered cracked cylinder head at his Mazda dealership.
 
In that thread there’re 5 cases of cracked cylinder head on the 2.5L with CD, and 1 case on the 2.5T. A member waited 8 months for a new head to fix the engine.

I remember there’s another earlier thread with several reports of cracked cylinder head on the 2.5L with CD, and at the time Mazds was replacing the whole engine for the cracked head. Some even posted a couple of pictures which showed several removed engines suffered cracked cylinder head at his Mazda dealership.
I counted 4, two CX-5 and two Mazda 3, though not all are confirmed cracked cylinder heads, but your point is well taken. The Reddit thread OP states his is a CD problem. A couple after than can be deduced knowing the CX-5 turbo versions were not sold until Nov. 2019. Then as the posts get more current you start running into the issue of which engine the poster is talking about. That's when I stopped reading. Some of these reports may be redundant across platforms.

So, yes, there are instances to be sure.
 
In that thread there’re 5 cases of cracked cylinder head on the 2.5L with CD, and 1 case on the 2.5T. A member waited 8 months for a new head to fix the engine.

I remember there’s another earlier thread with several reports of cracked cylinder head on the 2.5L with CD, and at the time Mazds was replacing the whole engine for the cracked head. Some even posted a couple of pictures which showed several removed engines suffered cracked cylinder head at his Mazda dealership.
After about three weeks they be hearing from my local Ag and I'd file a request they buy back my car under the lemon law.
 
A car manufacture won’t issue a TSB of SA unless there’re significant number of reports about the problem.
I question this assumption. It should not take too many instances of a part failure resulting in an expensive repair to get the attention of the manufacturer. They would want to determine if there is a design flaw or repeating manufacturing error that will cause outsized warranty repairs in future production and nip it in the bud as soon as possible.

If it turns out to be just a batch of parts from a temporary manufacturing error that has since been corrected that results in some percentage failure rate, that's another matter. But you don't know if you don't investigate and it can take quite some time to get to the bottom of it and develop a fix if necessary.

The Service Bulletin for the new CD cylinder head assembly doesn't provide a clue as to the reason for it unlike most TSBs.
 
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You can’t mix safety recalls with TSBs and Service Alert. Very few engine fires may trigger a safety recall, but there has to be significant number of failures to prompt the car manufactures to issue a TSB or a SA.

Fair, but I'm still pretty sure that there is no ruleset for when a manufacturer issues a TSB or SA. It's up to their discretion. While a TSB or SA is more likely to be issued for a more common problem, they are not only issued for common problems, as you assert.


Thanks for posting this. Over past several months, I have read several CX-5 non-turbo CD with head problems both on mazda247 forum and reddit but don't have time to research and post them all here to prove they exist.
I knew this was more widespread than some people say.
The Mazda forum thread was very useful.
Thanks again.

It would have been faster and easier for you to just do the research..


In that thread there’re 5 cases of cracked cylinder head on the 2.5L with CD, and 1 case on the 2.5T. A member waited 8 months for a new head to fix the engine.

I remember there’s another earlier thread with several reports of cracked cylinder head on the 2.5L with CD, and at the time Mazds was replacing the whole engine for the cracked head. Some even posted a couple of pictures which showed several removed engines suffered cracked cylinder head at his Mazda dealership.

Context is important when making statements like this. If you can find the post, please quote it here for reference. I could be wrong, but I'm pretty sure the user who posted the picture wasn't even sure that the engines all had the same problem. They may have been NA engines with or without CD, or they may have been 2.5T engines. Maybe they didn't even have cylinder head cracks, I'm pretty sure that was just an assumption (again, I could be misremembering).
 
So, how many actual reports of engine problems on the NA CX-5 with CD across all of the platforms discussed so far? Just so we have a running tally.
 
I counted 4, two CX-5 and two Mazda 3, though not all are confirmed cracked cylinder heads, but your point is well taken. The Reddit thread OP states his is a CD problem. A couple after than can be deduced knowing the CX-5 turbo versions were not sold until Nov. 2019. Then as the posts get more current you start running into the issue of which engine the poster is talking about. That's when I stopped reading. Some of these reports may be redundant across platforms.

So, yes, there are instances to be sure.
Turbo CX-5 came out b4 Nov 2019. Bought our turbo in Aug 2019. They were out either spring or early summer 2019.
 
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