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

[walt]

So. Is there any data that suggest if a redesigned head was used in production?
And if so when. We really like our 2020 CX-5. But I don't have a lot of confidence
that a redesigned head even exist unless Mazda can and will answer this question.
And what was the change in the design? Someone must know.
My only complaint is the cheap spare tire. I don't like traveling long distance with it. But otherwise it's a keeper. Thanks.

 

[181962]

So. Is there any data that suggest if a redesigned head was used in production?
And if so when. We really like our 2020 CX-5. But I don't have a lot of confidence
that a redesigned head even exist unless Mazda can and will answer this question.
And what was the change in the design? Someone must know.
My only complaint is the cheap spare tire. I don't like traveling long distance with it. But otherwise it's a keeper. Thanks.

For non-turbos, Mazda has issued (and updated a couple of times) the TSB attached below for a redesigned cylinder head assembly. No problem that this redesign is intended to fix is identified in the TSB. That is somewhat encouraging but does give one pause.

On the other hand, the similar TSB for turbos linked below identifies a known problem--cracked cylinder head and coolant leak.

I don't think you identified which engine you have.

Anecdotally, the cracked cylinder head appears to be quite a bit more frequent in turbo models. The poll in the CX-9 sub-forum shows 53 reported engine replacements which is quite a few considering the low sales volumes and some small slice of owners posting here.

While there have been reports of oil leaks in non-turbos I'm not sure anybody has reported a confirmed cracked cylinder head.

 

[ddingle]

This is more or less an FYI for this group, but my 2020 Reserve CX5 with 40000 miles had a check engine light on for a miss on cylinder 3. Dealer could not find anything and reset it. A few days later it went on again. This time the dealer called Mazda support in California and after checking for and finding low compression in the 3 cylinder they are replacing the head in warranty. Actually the Cx9 loaner with the same engine seems peppier so hopefully my CX5 will improve once the head is replaced. Not sure if this is part of the problem with cylinder heads on 2019 versions I have read about.

 

[walt]

So it is likely that the redesigned head is only available for repairs and
never used during production. Unless current production.
Here is a link to quickly inspect for the cracked head. May or may not apply to certain vehicles. Mostly 2.5L non turbo with CD. As mentioned in this video. Cylinder no. 3 is also mentioned.
watch

 

[ddingle]

This is more or less an FYI for this group, but my 2020 Reserve CX5 with 40000 miles had a check engine light on for a miss on cylinder 3. Dealer could not find anything and reset it. A few days later it went on again. This time the dealer called Mazda support in California and after checking for and finding low compression in the 3 cylinder they are replacing the head in warranty. Actually the Cx9 loaner with the same engine seems peppier so hopefully my CX5 will improve once the head is replaced. Not sure if this is part of the problem with cylinder heads on 2019 versions I have read about.

Got the car back. They noted 118 pounds in 1,2 and 4 cylinders and 80 pounds of compression on Cylinder three. They also noted it was the exhaust valve that wasn't working properly. Would be interesting to know why it failed, but must have been defective as per the TSBs . The car idles MUCH better now and has about 10 percent more get up and go. Might try a tank of premium fuel to see what the potential is.

 

[ddingle]

Got the car back. They noted 118 pounds in 1,2 and 4 cylinders and 80 pounds of compression on Cylinder three. They also noted it was the exhaust valve that wasn't working properly. Would be interesting to know why it failed, but must have been defective as per the TSBs . The car idles MUCH better now and has about 10 percent more get up and go. Might try a tank of premium fuel to see what the potential is.

I did confirm my vin number was in the range of vehicles with the suspect design which were built before June 9th 2020. They did replace the exhaust manifold as well as the cylinder head. I watched a couple of videos describing how Mazda was in the initial skyactiv G turbo design routing the exhaust in such a way to improve air draw in the manifold from cylinder and avoid nearby next in line cylinders getting back fed with heat and increasing the chance of detonation and other bad things. I suspect that design wasn't working quite right and was re-designed for production past June 9th 2020. Meanwhile my CX5's number 3 exhaust valve ended up being compromised by the original exhaust manifold design. The Tsb pointed to coolant leaks in the engine as a worse symptom of the design issue. Something like that anyway.

 

[walt]

"I suspect that design wasn't working quite right and was re-designed for production past June 9th 2020."

Would this apply to non-turbo 2.5L? Or is there really any way to tell?
My 2020 CX-5, 2.5L, has build date of 7-20 on the name plate inside the door jamb. I really like this car but don't want to wait for that day.
26 mpg average.

 

[ddingle]

"I suspect that design wasn't working quite right and was re-designed for production past June 9th 2020."

Would this apply to non-turbo 2.5L? Or is there really any way to tell?
My 2020 CX-5, 2.5L, has build date of 7-20 on the name plate inside the door jamb. I really like this car but don't want to wait for that day.
26 mpg average.

This is a turbo related issue, but I just have a cursory understanding of the problem. . The exhaust manifold is different with the Turbo. I don't believe there has been any sort of recall on the CX5.

 

[ddingle]

The manifold is definitely different on the turbo. This is a video describing the technology Mazda is using with the Turbo 2.5 Skyactiv G engine. Mazda CX9 4-Cylinder Turbo Engine Explained
They pair the exhaust manifold pipes and firing order in such way to help draw more exhaust out faster with additional suction from the adjacent cylinder of the pair. Keeping cylinders cooler. At lower rpms they force the exhaust into a small port away from the normal ports which increases pressure and spools up the Turbo quicker reducing lag. At higher rpm the larger ports are switched back in. I am wondering if on the units built before June 9th 2020 they discovered some sort of issue with the exhaust manifold system design and fixed the design or the design is good and some early manifolds were made out of specification somehow. They also feed recycled exhaust back from a specific exhaust port through a cooler and then into the air intake to decrease the chance of detonation and allow more horsepower. Whatever the problem it seems to have caused premature failure of the exhaust valves on the #3 cylinder of my CX5.

 

[yrwei52]

This is a turbo related issue, but I just have a cursory understanding of the problem. . The exhaust manifold is different with the Turbo. I don't believe there has been any sort of recall on the CX5.

If you read the beginning of this thread the problem is a non-turbo related issue on the 2.5L with cylinder deactivation. Mazda redesigned the cylinder head from original SkyActiv-G 2.5L to accommodate the new components only for the cylinder deactivation feature. Apparently this redesign did affect the longevity of the cylinder head, although the redesigned cylinder head on the 2.5T seems to be more problem‐prone.

 

[ddingle]

If you read the beginning of this thread the problem is a non-turbo related issue on the 2.5L with cylinder deactivation. Mazda redesigned the cylinder head from original SkyActiv-G 2.5L to accommodate the new components only for the cylinder deactivation feature. Apparently this redesign did affect the longevity of the cylinder head, although the redesigned cylinder head on the 2.5T seems to be more problem‐prone.

So both the Turbo 2.5 and the NA 2.5 have cylinder head issues with different TSBs associated with them. Not surprisingly both engines have significantly different designs for the cylinder head and manifold. The cylinder deativation (not on the Turbo version) would seem to be causing the issue with the NA engine, but no real indication of what the problem is with the Turbo other than coolant/oil leaks. In my case there wasn't any sign of oil or coolant leaks. My idle was occasionally rough and finally the check engine light came on which after it occurred a second time the dealer checked with Mazda and they suggested compression check. Compression in cylinder 3 was low so they replaced the head and exhaust manifold under drivetrain warranty. The tech indicted it was exhaust valve in cylinder three that had failed in some fashion. Almost seems like a different issue causing the cylinder head replacement in my turbo's case? Also since they replaced the exhaust manifold (which isn't really part of the head) and they design the exhaust manifold specifically to allow the Turbo version to pull more heat from the cylinders as they are operating. I suspect that the exhaust manifold may not have worked as well at pulling heat away as originally intended which overheats the valves causing failure. Anyone know any more about what is actually causing the failures on Turbo 2.5s?

 

[ctbale]

TSB 01-013/21. 2.5T

 

[ddingle]

TSB 01-013/21. 2.5T

My situation seems a little out of whack with the Tsb. Certainly the techs at the dealership were not looking at the cylinder head as an issue when I came in with the P303 code on a check engine light showing a misfire on cylinder 3. The other code DTC 111a mentioned in the Tsb was more indicative of overheating and a cylinder head issue. In the TSB deformation of the manifold is mentioned as a source of the cracked head so for some reason they get hot. Like a design mistake for the manifold. This really seems like this issue should be a recall for all 2019-20 2.5 Turbos built before June 9th 2020. Anyone looking at a used vehicle with this engine within the Vin range should be extremely cautious. Same holds true for the standard NA 2.5.

 

[yrwei52]

My situation seems a little out of whack with the Tsb. Certainly the techs at the dealership were not looking at the cylinder head as an issue when I came in with the P303 code on a check engine light showing a misfire on cylinder 3. The other code DTC 111a mentioned in the Tsb was more indicative of overheating and a cylinder head issue.

Yes, your situation seems to be different.

In the TSB deformation of the manifold is mentioned as a source of the cracked head so for some reason they get hot. Like a design mistake for the manifold.

I’ve always felt the problem is due to the redesign of the head from the original 2.5L NA which has weakling certain area of the head. But as you said, the redesigned exhaust manifold could be the culprit of the whole issue.

This really seems like this issue should be a recall for all 2019-20 2.5 Turbos built before June 9th 2020. Anyone looking at a used vehicle with this engine within the Vin range should be extremely cautious. Same holds true for the standard NA 2.5.

I agree that a recall should be issued for the 2.5T assembled before June 9th 2020. But you got to remember the same 2.5T is also used on the CX-9 since 2016 MY which also suffered the same issue. That would be a huge expense for the Mazda and Mazda won’t initiate such recall except they’re forced to do so by the NHTSA. That’s why those 2.5T owners who have suffered the cylinder head crack issue should file a complaint at the NHTSA website. The more the complaint filed, the better chance the NHTSA will initiate a recall like the recall on the falling rocker arms on the 2.5L NA with cylinder deactivation used on the 2018 CX-5.

 

[181962]

The tech indicted it was exhaust valve in cylinder three that had failed in some fashion.

Based on that comment, your problem is more closely related to the following TSB addressing problems arising after a valve stem seal modification:

https://static.nhtsa.gov/odi/tsbs/2021/MC-10203724-0001.pdf

Different symptoms however; you report different codes and no oil loss. There is a class action lawsuit pertaining it faulty valve stem seals, but again the thrust of the complaint is oils consumption.

As for NA engines with cylinder deactivation, there is a separate TSB for a redesigned cylinder head (see post #102) but no specific problem is identified. That NA TSB is somewhat concerning, but stuff is always being tweaked for one reason or another, such as the turbo valve stem seal being modified which no one would know about if a problem with it had not been identified. Complaints about oil consumption or compression loss on the NA cylinder deactivation engine are few and far between in these pages, if any at all.

 

[ddingle]

Based on that comment, your problem is more closely related to the following TSB addressing problems arising after a valve stem seal modification:

https://static.nhtsa.gov/odi/tsbs/2021/MC-10203724-0001.pdf

Different symptoms however; you report different codes and no oil loss. There is a class action lawsuit pertaining it faulty valve stem seals, but again the thrust of the complaint is oils consumption.

As for NA engines with cylinder deactivation, there is a separate TSB for a redesigned cylinder head (see post #102) but no specific problem is identified. That NA TSB is somewhat concerning, but stuff is always being tweaked for one reason or another, such as the turbo valve stem seal being modified which no one would know about if a problem with it had not been identified. Complaints about oil consumption or compression loss on the NA cylinder deactivation engine are few and far between in these pages, if any at all.

Yes, in my case the compression was 40 pounds lower in cylinder 3 than in the other cylinders. That would seem to indicate the valve(s) was/were leaking enough to cause a misfire as indicated by the P303 check engine light. The TSB suggested the issue they were describing would not cause any harm to the engine, but in my case there certainly was concern about damage further down the line with the catalytic converter exposure to unused fuel. No indication of oil use in my case either.

 

[ceric]

That’s why those 2.5T owners who have suffered the cylinder head crack issue should file a complaint at the NHTSA website. The more the complaint filed, the better chance the NHTSA will initiate a recall like the recall on the falling rocker arms on the 2.5L NA with cylinder deactivation used on the 2018 CX-5.

NHTSA only issues a recall (or forcing it) if the specific defect causes safety concerns.
A warning light on the dash (losing a bit power) might not a safety issue (even if I think it is like you do) from the perspective of NHTSA.

Amazingly, a brake light defect can trigger a recall... or a power seat that moves while driving.
Both happened to my ex-Prius.

 

[nolig36]

So our na 2018 started smoking. Made a huge mess of entire rear of car. Added a quart over about 500 miles of driving. After I cleaned up oil, I ran engine a few seconds again and seems oil starts in the area I circled. Is there anything else that might leak oil in this area? I had to top off coolant recently too, but not much. Couldn't more than the head get damaged from this problem?

Thanks

 

[yrwei52]

So our na 2018 started smoking. Made a huge mess of entire rear of car. Added a quart over about 500 miles of driving. After I cleaned up oil, I ran engine a few seconds again and seems oil starts in the area I circled. Is there anything else that might leak oil in this area? I had to top off coolant recently too, but not much. Couldn't more than the head get damaged from this problem?

Thanks

Hope you still have 5-year / 60,000-mile powertrain warranty to get the cracked cylinder head replaced.

 

[nolig36]

Hope you still have 5-year / 60,000-mile powertrain warranty to get the cracked cylinder head replaced.

I do have warranty. Waiting to talk to Mazda and praying they have the head and loaner. Can they try to say it is just the gasket.