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

Much ado about nothing - Mazdas CD may in reality be technology for technologys sake - but in my circumstances it does help greatly with gas mileage ( add 4 mpg on the fwy for me on ever gallon !- long drives - flat 75-85 mph 35-38mpg ) and zero effect on reliability , maintainence or power -- I use REGULAR gas , my insurance is rock bottom , my tires will last 60k ! -CD IS on millions of Mazda autos for what 5-6 years !
- and the recent pull back on oct / nov prod. discontinuing i-stop & Cd
says due to parts shortage , but it ls likely a cost cutting measure - as those 2 systems arent inexpensive and Mazda already raised the MSRP quite a bit in the CX5 and now this creates even more margin- which covers increasing manufacturing / parts costs - Most drivers dont care about CD or know , and I-stop is absurd in my opinion - So fine -
I happen to like CD - but inexperienced people who havent been on the planet long or understand engineerihg and have not owned 20 cars , often fear anythihg new or different, because they listen to narcassicistic know it alls ( who sew fear based on one thing that happended- many dont even own CX5s ! .also . by reading internet dribble without all the facts
- Mazda is a different company- hence rotary engines - reiability issues ;-)
- CD does save me $$ - I had the $$ for the Turbo - but frankly , turbo engines just dont last as long as NAs , and can be very prone to all kinds of engine issues / far far far more than one preventive recall in early 2019 for CD - Turbos have had over 20 major issues , yet CD gets bashed , but continue to run today trouble free all over the world , many with 200+ k
mi and thats just a fact -

then on the Turbos ( T = trouble I was looking at higher insurance, poor gas mileage , premium fuel to get the proper power, more tire wear , brake wear , they run hot , need more spark plug changes, burn oil , tons more moving parts that can fail - and do, but owners idealize them because ego wont let them speak these truths - who wants to admit. these truths after shelling out $$!!
- Each to their own , but - so many people who review the CX-5 say , the great thing about it , you dont need to drive it fast to enjoy it - and thats true !
Yeah there was a recall on the CD - 2018 ? - But to date the absolute least reliable CX-5 which all car people avoid - 2016 cx-5 - electrical/ and any
Turbo ! ----on CD it was a preventative recall mainly( nobody was hurt ) and those craked heads ( manily on turbos ) was also fractionally minor and there ZERO - repeate. ZERO evidence ( thats any fact that shows its connection ) thst CD has caused ANY damage to ANY part if the 2.5 NA engine !!!Which is ranked 9/10 ! , less than a fraction of 1% of all vehicles had a craked head ( theres mainly Turbos with craked heads ) and those DO HAVE EVIDENCE that the TURBO was the cause !! FACT - Yet self-proclaimed " experts " in here say theres NAs with crakedvheads - yeah - yours !
so its just a bunch of wannbe know it alls who sew panic over nothing -
An NA/w CD will out last a Turbo by a factor of at least 2-3 x likely way more --without any major engine work - its just a fact - So Im in for the long haul with my NA - like every other Mazda I have , and they all seem to clock 100, 200,300k without issues? Theres so many ancillary factors & issues not mentioned in here - like on these craked heads ( manily turbos ) - the circumstances on those are not even mentioned here - and Im not going to get into a pissing contest to prove what occured- but saying it was NAs with CD that had the 1/1000th of 1% of craked heads is like saying that airbag recalls on Toyotas .....all had 4 wheels too- ! No Sh-t
- but I put my $$ on the NAw CD ( have 2 ) and odds are with me they will run 200k mi with ease - and wont cost me much to do it ! Turbos are fun but , stress many engine parts , run hot - and will cost you big time as we watch its operating costs continue to go up - heck this blog is ltttered with turbo troubleshooting , and these are not sports cars- which is why i suspect many break them as some think if theres a " turbo "
its a sports car " not , they are compact , economy suvs

- ! If Mazda sincerely believed existing CD was an issue - it could be deactivated with a 10min pit stop at the dealer- currently CD will NOT engauge in P,R ,N while running - thus its. easy to non-mechanically disable - but thats not happening - I say pull the Turbos - they have bulk cases of craked heads, leaks , burning oil issues , run hot, blown head gaskets , ruined transmissions ++++all kinds of other failures and you will pay for owning one - If you want to drive fast , have the scratch - and dont plan on keeping it 15?years - gfi - Many pubs/ car&driver etc all say " get the turbo " - but thats a track test drive reaction at about the way it drives with more power / never a word about the overall REAL world cost increases and cost to maintain , fuel , insure , etc , and not real world sound advice -- Compare these 2
experts on CD - VS TURBO -and you decide !


 
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An NA/w CD will out last a Turbo by a factor of at least 2-3 x likely way more --without any major engine work - its just a fact

Turbos have had over 20 major issues

heck this blog is ltttered with turbo troubleshooting

bulk cases of craked heads, leaks , burning oil issues , run hot, blown head gaskets , ruined transmissions

For someone who uses the word "facts" a whole bunch, you don't provide much evidence to support your cases, only exaggerated assumptions and conclusions. I see a lot that goes on in this forum. Between the 2.5T and the 2.5 NA w/ CD, there are more reports of failures from owners of the NA engine.

There have also been a few reports of 2016-17 CX-9s with over 250k mi on the original engine/turbo/transmission. There is no denying that a turbocharger introduces more points of failure on an engine, but that doesn't guarantee that an engine will fail at X miles, or even at all.

Citing Scotty Kilmer as a credible resource is a far, far reach lol. For years the guy talked poorly about Mazdas without knowing anything about them. He's got videos titled "why not to buy a turbocharged car" and "never buy a brand new car", yet he owns a 2024 Mazda CX-90. Just look at his video uploads, it's a masterclass in writing clickbait titles.


In any case, you've made your opinion known. Let's get back to the thread topic please.
 
One thing I never mentioned was the driving condition of my 2018 with the head issue. When we last had it looked at by the dealer a couple of weeks back was when the first engine oil leak was spotted. At the oil change six months before that there was no sign of any leak at all.

When the indie shop discovered the head issue, there was no smoke whatsoever and the car ran perfect. Despite the fact that we had three oil leaks (oil pan gasket, timing chain cover and head crack) and there was no outward sign of any issues at all.
 
When the indie shop discovered the head issue, there was no smoke whatsoever and the car ran perfect. Despite the fact that we had three oil leaks (oil pan gasket, timing chain cover and head crack) and there was no outward sign of any issues at all.
The odds are against 3 different oil leaks occurring at the same time, possibly the head crack was the source for the oil that spread all over the engine. Doesn't really matter for the purposes of this conversation though.

How were you able to sell a car in this condition so quickly? How much of a hit did you have to take in price due to the engine oil leak(s)?
 
The odds are against 3 different oil leaks occurring at the same time, possibly the head crack was the source for the oil that spread all over the engine. Doesn't really matter for the purposes of this conversation though.
In my case there also was no warning at all. Suddenly my oil light came on. I had also had my oil changed a couple of months before that with no sign of a leak. Dealership discovered the cracked cylinder head. But oil had been sprayed all over the engine, everywhere that oil could get into, so I also suspect that was the issue rather than three separate leaks. The indie shop probably thought it was three leaks, not being familiar with the cracked head problem. The dealership, however, probably knew what to look for right away since they have been dealing with this for a while. Just my not-at-all-expert opinion.
 
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Much ado about nothing - Mazdas CD may in reality be technology for technologys sake - but in my circumstances it does help greatly with gas mileage ( add 4 mpg on the fwy for me on ever gallon !- long drives - flat 75-85 mph 35-38mpg ) and zero effect on reliability , maintainence or power -- I use REGULAR gas , my insurance is rock bottom , my tires will last 60k ! -CD IS on millions of Mazda autos for what 5-6 years !
If you can get 35~38 mpg driving at 75~85 mph, which beats 2023 CX-5 EPA highway rating by many miles (16.7% ~ 26.7%!), that’s great! But most people struggle to match EPA fuel economy ratings including me, especially if you drive at 85 mph!

0F7DD2A0-7ED0-4C7E-AF37-FA0136BB6D64.jpeg


Then how do you know there’s zero effect on reliability from cylinder deactivation on the 2.5L NA which is based on what? We’ve already seen enough reports on cracked cylinder head from 2.5L NA with CD, and a video showed the 2 mm thin wall at the cracked area, but we’ve never seen ANY reports on cracked head from 2.5L NA without CD which is older and is having a lot more miles now.

The recent TSB has also exposed Mazda used more traditional single clutch with a more aggressive material to survive early lockup on the transmission with CD, and now is having issues.

2017~2024 CX-5 Chirp Noise from Automatic Transaxle on 3-4 upshift - Bulletin 05-005/23

Not to mention the history of cylinder deactivation doesn’t speak well for the long term reliability due to cylinder deactivation would cause intermittent uneven heat distribution in the top of the engine. The heat generated by the combustion process is even and constant in normal firing, and then it isn't under cylinder deactivation. Compression and decompression of the sealed cylinders is still going on with deactivated cylinders while the pistons traveling up and down, which consumes energy. The switchable hydraulic lash adjusters used to deactivate cylinders are controlled by oil pressure with very fine tolerances. Any loss of pressure or build up could mess with the process. And that’s why the recall and a TSB for clapping valve noise all related to switchable HLAs on the 2.5L NA with CD.

GM、Chrysler、and Honda have all had problems with these cylinder deactivation systems for many, many years, despite multiple efforts to revise and improve the systems. It just seems to be a significant risk, including premature ring and cylinder wall wears.


- Most drivers dont care about CD or know , and I-stop is absurd in my opinion - So fine
Yes, agreed.


- I happen to like CD - but inexperienced people who havent been on the planet long or understand engineerihg and have not owned 20 cars , often fear anythihg new or different, because they listen to narcassicistic know it alls ( who sew fear based on one thing that happended- many dont even own CX5s ! .also . by reading internet dribble without all the facts
Don’t agree. Actually I found “inexperienced people who havent been on the planet long or understand engineerihg and have not owned 20 cars”, often NOT fear anythihg new or different because they don’t know the potential problems that could happen.


- Mazda is a different company- hence rotary engines - reiability issues ;-)
Yes, Mazda has been not afraid of trying new innovations, rotary engines、SkyActiv series engines and transmissions 、HCCI / SPCCI / SkyActiv-X 2.0L, to name a few. But how many of them are still here? Many of them are gone due to reliability issues.


- CD does save me $$ - I had the $$ for the Turbo - but frankly , turbo engines just dont last as long as NAs , and can be very prone to all kinds of engine issues / far far far more than one preventive recall in early 2019 for CD - Turbos have had over 20 major issues , yet CD gets bashed , but continue to run today trouble free all over the world , many with 200+ k
mi and thats just a fact -
Even if you can get 35~38 mpg driving at 75~85 mph on the highway, how much money you can really save? ~$3,500 if 38 mpg is all you have in 100,000 miles. But one cracked head could cost you ~$7,000 nowadays. Is that worth a gamble? Not for me. The 2.5T has its own cracked head problem, but at least Mazda had updated the head and exhaust manifold gasket to fight against crack.

If I have to choose one between the 2.5L NA with CD and the 2.5T, I’d choose the 2.5T even if the long-term reliability is my first priority. But in reality I’d choose none of them.


⋯ Yeah there was a recall on the CD - 2018 ? - But to date the absolute least reliable CX-5 which all car people avoid - 2016 cx-5 - electrical/ and any
Turbo !
----on CD it was a preventative recall mainly( nobody was hurt ) and those craked heads ( manily on turbos ) was also fractionally minor and there ZERO - repeate. ZERO evidence ( thats any fact that shows its connection ) thst CD has caused ANY damage to ANY part if the 2.5 NA engine !!!Which is ranked 9/10 ! , less than a fraction of 1% of all vehicles had a craked head ( theres mainly Turbos with craked heads ) and those DO HAVE EVIDENCE that the TURBO was the cause !!
At least I haven’t seen any major problems such as cracked cylinder head or clapping valve noise reported on the 2016 CX-5. So based on what you said the 2016 CX-5 the absolute least reliable CX-5 so that I can dump mine ASAP! 😳


FACT - Yet self-proclaimed " experts " in here say theres NAs with crakedvheads - yeah - yours !
so its just a bunch of wannbe know it alls who sew panic over nothing -
An NA/w CD will out last a Turbo by a factor of at least 2-3 x likely way more --without any major engine work - its just a fact - So Im in for the long haul with my NA - like every other Mazda I have , and they all seem to clock 100, 200,300k without issues? Theres so many ancillary factors & issues not mentioned in here - like on these craked heads ( manily turbos ) - the circumstances on those are not even mentioned here - and Im not going to get into a pissing contest to prove what occured- but saying it was NAs with CD that had the 1/1000th of 1% of craked heads is like saying that airbag recalls on Toyotas .....all had 4 wheels too- ! No Sh-t
- but I put my $$ on the NAw CD ( have 2 ) and odds are with me they will run 200k mi with ease - and wont cost me much to do it ! Turbos are fun but , stress many engine parts , run hot - and will cost you big time as we watch its operating costs continue to go up - heck this blog is ltttered with turbo troubleshooting , and these are not sports cars- which is why i suspect many break them as some think if theres a " turbo "
its a sports car " not , they are compact , economy suvs
So you want to ignore the cracked head reports here on the 2.5L NA with CD, and you’re in for the long haul with the 2.5L NA with CD, and you believe it will run 200K miles with ease, that’s your choice. But I really don’t feel a 2.5L NA w/CD can outlast a 2.5T simply based on the CD history. And if you want to compare the failure rate or percentage on cracked cylinder head, @GTA-CX9 here said the best:

This is the thing, I often see the % amount of failures brought up as a reassurance. But this isn't like a sensor that goes faulty or a malfunctioning sunroof. The threshold for a % that would make me not worry is way low when the repair is thousands of bucks.

And here’s a recent sad story from a CX-9 owner who couldn’t afford $7,000+ to replace the cracked cylinder head:

44,000 yeah I have already just kinda accepted that the dealership and Mazda are okay with just not helping. I am just going to let them repossess the car because I do not have another choice. This is terrible timing with car market the way it is thank you for the advice


- ! If Mazda sincerely believed existing CD was an issue - it could be deactivated with a 10min pit stop at the dealer- currently CD will NOT engauge in P,R ,N while running - thus its. easy to non-mechanically disable - but thats not happening - I say pull the Turbos - they have bulk cases of craked heads, leaks , burning oil issues , run hot, blown head gaskets , ruined transmissions ++++all kinds of other failures and you will pay for owning one - If you want to drive fast , have the scratch - and dont plan on keeping it 15?years - gfi - Many pubs/ car&driver etc all say " get the turbo " - but thats a track test drive reaction at about the way it drives with more power / never a word about the overall REAL world cost increases and cost to maintain , fuel , insure , etc , and not real world sound advice -- Compare these 2
experts on CD - VS TURBO -and you decide !


I don’t believe you can easily to disable the cylinder deactivation on the 2.5L NA with a 10-minute stop at the dealership at this time. A new PCM has to be developed which we haven’t seen any available from a third party. If it’s that easy to disable the CD on the 2.5L NA, there would be one available for Mazda owners who really dislike the CD, like the device which is already available to disable Mazda’s i-stop on the market.
 
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⋯ I see a lot that goes on in this forum. Between the 2.5T and the 2.5 NA w/ CD, there are more reports of failures from owners of the NA engine.
I have to say there’re more cracked cylinder head cases on the 2.5T than the 2.5L NA with CD based on all the reports here. The other evidence is Mazda had issued a TSB for the 2.5T and updated the cylinder head and exhaust manifold gasket to fight against cracked head, but Mazda has done nothing to the cracked head problem on the 2.5L NA with CD. The only thing Mazda had done to the 2.5L NA with CD was they issued a Service Alert with a new part number to group everything together for the ease of head replacement job.


⋯ Citing Scotty Kilmer as a credible resource is a far, far reach lol. For years the guy talked poorly about Mazdas without knowing anything about them. He's got videos titled "why not to buy a turbocharged car" and "never buy a brand new car", yet he owns a 2024 Mazda CX-90. Just look at his video uploads, it's a masterclass in writing clickbait titles.

And Scotty Kilmer also made this《Here's Why Mazda is About to Be the Best Car Brand》video:


Can’t blame him, he needs to make living too ⋯ ;)
 
I don’t believe you can easily to disable the cylinder deactivation on the 2.5L NA with a 10-minute stop at the dealership at this time. A new PCM has to be developed which we haven’t seen any available from a third party. If it’s that easy to disable the CD on the 2.5L NA, there would be one available for Mazda owners who really dislike the CD, like the device which is already available to disable Mazda’s i-stop on the market.
If the CD is controlled by the PCM it can be disabled by reflashing the PCM with modified software. It does take longer than 10 minutes but it can be done. Dealers may not have the equipment or training to perform the task. The design engineers would have the capability and would have to create a work instruction, required fixtures, and training for the dealers.

I have done this for GM in a past life.
 
I see no reason to believe that disabling CD would have any affect on the cracked cylinder head issue. Disabling CD might help with the torque converter issue but we don't know enough about the failure mechanism there yet to speculate.

There may be legal issues with the EPA that would prevent Mazda from ever rolling out a fix that disables CD.
 
If the CD is controlled by the PCM it can be disabled by reflashing the PCM with modified software. It does take longer than 10 minutes but it can be done. Dealers may not have the equipment or training to perform the task. The design engineers would have the capability and would have to create a work instruction, required fixtures, and training for the dealers.

I have done this for GM in a past life.
Well if you want to modify the PCM program to disable the cylinder deactivation you need the source code, and depending on the software design it could be everywhere you need to modify the code. A few third party companies are willing to pay the money to get the PCM source code from Mazda for tuning purpose if Mazda is willing to sell. Mazda itself, although they can do it, apparently has no intention to disable the CD in the near future.

Reflashing the PCM with updated version isn’t a big deal, but getting the source code and modified it to disable the CD can be a big problem.
 
I see no reason to believe that disabling CD would have any affect on the cracked cylinder head issue. Disabling CD might help with the torque converter issue but we don't know enough about the failure mechanism there yet to speculate.

There may be legal issues with the EPA that would prevent Mazda from ever rolling out a fix that disables CD.
Agreed.

Based on YouTube video from Ukraine / Russia the cracked area of his 2.5L NA with CD is only 2 mm thin which is much thinner than other cylinder heads. IMO Mazda modified the original head for CD components such as the (larger) switchable hydraulic lash adjusters and compromised the structure strength. Yes even if the CD got disabled, the crack would be potentially still happening. But without CD it can prevent other long-term ill effects exposed by the history of CD such as premature wear on piston rings and cylinder walls.
 
Agreed.

Based on YouTube video from Ukraine / Russia the cracked area of his 2.5L NA with CD is only 2 mm thin which is much thinner than other cylinder heads. IMO Mazda modified the original head for CD components such as the (larger) switchable hydraulic lash adjusters and compromised the structure strength. Yes even if the CD got disabled, the crack would be potentially still happening. But without CD it can prevent other long-term ill effects exposed by the history of CD such as premature wear on piston rings and cylinder walls.

I feel like I've read this post before... ;)

2mm.png
 
Not to excuse a bad design which we can see that it is, not going to do that but I much prefer 5W-30.

5W-30 just works better than 0W-20 at high pressures and temperatures, and the Skyactiv engine is a high compression engine. I'll spread the gospel whenever I can. Get rid of that lightweight, non-noise insulating oil and run the oil Mazda specifically recommends in the rest of the world.


0w20.png



5w30.png
 
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Assuming you get a CX-5 that isn’t affected by the cracked cylinder head issue that causes a “premature“ failure that might total the vehicle if it’s out of warranty, how long can you realistically expect the vehicle to last?
For as old and “proven“ as the model and powertrain is, for some reason, I’m not seeing CX-5 owners reporting super high mileage on original powertrains on Mazdas like I do with many Toyotas and some Hondas.
 
 
Assuming you get a CX-5 that isn’t affected by the cracked cylinder head issue that causes a “premature“ failure that might total the vehicle if it’s out of warranty, how long can you realistically expect the vehicle to last?
For as old and “proven“ as the model and powertrain is, for some reason, I’m not seeing CX-5 owners reporting super high mileage on original powertrains on Mazdas like I do with many Toyotas and some Hondas.
For one thing, Toyota owners in particular will not miss an opportunity to tell someone how many miles they have on their vehicle.
 
I’ve got 83k miles on my ‘12 Lexus GX 460 (Toyota Land Cruiser Prado) :)

I doubt I will ever reach any notable mileage levels anyone will care about. I just don’t rack the miles up like many do.. my ‘07 Infiniti G35X(V36 (Nissan Skyline) & purchased new)) has around 125k miles
 
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Well, OK. I was hit by this damned thing as well back in November, we simply traded the car the next day.

But my question is this....the 2.5 is used in the VAST majority of Mazdas now being sold. Does this affect those in the Mazda3 as well? I'd love to have one of those, but am very, very, leery of this engine until I can be assured that this issue has been properly dealt with.
 
My understanding is it can effect any NA 2.5L engine with cylinder deactivation. The 2.5 Turbo also had an issue with cracking cylinder heads but instead of leaking oil it leaked coolant. But unlike the NA 2.5, the turbo's cylinder head was redesigned to prevent future cracks. (No indication that the 2.5 non-turbo head was redesigned, and I've seen reports of the head cracking in NA 2.5L 2022 CX5s)
 

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