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

[walt]

Still on topic I think. Do overseas models, Japan, EU, and more have the CD?

 

[p38cyq]

EU : Yes.

 

[ctbale]

Just wanted to post a quick tip for my fellow Canadian consumers, as I haven’t seen it mentioned in this entire thread.

The 2018-2022 base GX trim does not have CD (it finally became standard on all Canadian trims starting in 2023). Also, for 2017, none of the trims have CD in Canada.

So if you’re like me and wanting to hopefully avoid the potential issues with the cracked cylinder heads (and you’re willing to live without the extra bells and whistles of the higher trims), I believe opting for the GX trim might be a good choice (or any trim in 2017) since I’ve only read that this issue seems to affect the 2.5L NA with CD and the 2.5 Turbo engines. Cheers.

The CD cracked heads and Turbo cracked heads are different.....but both are cracked heads so they are the same.....

 

[Flight200]

Does anyone have a rough percentage of CD and Turbo models with the cracked cylinder heads?
More or less than 1% of vehicles built?
I saw someone post that they had a 2022 that was affected which debunks the thought that it only affect 2019 and older models, but I assume most 22-24 models have low miles and may not show up in statistics for a few years.
I wonder what’s preventing Mazda from solving this issue for good especially since most of their vehicles other than the Miata and CX-90 are using this engine?
60K miles or 60 months warranty isn’t enough for me since I plan to keep the vehicle for 8-10 years assuming it never gets totaled out before that from a collision repair or mechanical repair issue like a cracked cylinder head out of warranty.
Thinking of just getting a Venza instead to not worry about it, but I actually prefer most things about the CX-5 other than this one serious issue.

 

[ctbale]

Does anyone have a rough percentage of CD and Turbo models with the cracked cylinder heads?
More or less than 1% of vehicles built?
I saw someone post that they had a 2022 that was affected which debunks the thought that it only affect 2019 and older models, but I assume most 22-24 models have low miles and may not show up in statistics for a few years.
I wonder what’s preventing Mazda from solving this issue for good especially since most of their vehicles other than the Miata and CX-90 are using this engine?
60K miles or 60 months warranty isn’t enough for me since I plan to keep the vehicle for 8-10 years assuming it never gets totaled out before that from a collision repair or mechanical repair issue like a cracked cylinder head out of warranty.
Thinking of just getting a Venza instead to not worry about it, but I actually prefer most things about the CX-5 other than this one serious issue.

Where was the post on the 22 cracked head?

 

[yrwei52]

Where was the post on the 22 cracked head?

Post #302. And posted the invoice in #304 to prove it.

It is still happening with the 2022 models. I just got my cylinder head replaced under warranty. It's a CX-5 with a skyactive engine; it's not the turbo. I bought it new in March of 2022 and it only has 13,000 miles on it. There were no warning signs or symptoms other than the low oil level light coming on. I have the oil changed twice a year, so that definitely shouldn't have happened. I stopped immediately so no damage was done to the engine. I hope the replacement head will last.

Actually Mazda has never updated the cylinder head on the 2.5L NA with cylinder deactivation. So the cracked head report on newer MYs from 2.5L NA with CD shouldn’t surprise anybody.

As for the failure rate or percentage on cracked cylinder head, this’s 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.

 

[SimpleCanuck]

I'm curious to know if any replacement cylinder heads have failed. Haven't been able to find any data on that.

 

[yrwei52]

I'm curious to know if any replacement cylinder heads have failed. Haven't been able to find any data on that.

It’d take a while to know. It took 3 ~ 4 years to expose the cracked head problem on the 2.5T; and it took a little less time to expose the cracked head problem on the 2.5L NA with CD. IMO the failure rate has to be lower on the 2.5L NA with CD, hence no updates on head intended by the Mazda. Only a new part number for a cylinder head assembly with most parts pre-installed ready to be installed.

The closest scare is this 2021 CX-9 which comes with updated head and exhaust manifold gasket from factory for the 2.5T. The Mazda dealer told the owner they replaced the cylinder head due to the finding of coolant in oil when they were performing the exhaust valve stem seal replacement by the oil consumption TSB. The oil leaking problem was still there after the fix. Eventually the dealer claimed the 2.5T actually needed only the cylinder head gasket, without changing all other necessary gaskets and seals such as exhaust manifold gasket when they replace the head gasket, and call it a day!

My 2021 CX-9 GT is with the dealership now getting the head replaced. It was in the dealership 3 weeks ago getting new seals due to the oil consumption issue at that time there was also coolant in the oil and they replaced the gasket head. Three weeks later, coolant leaking from the head, no coolant in the oil. Have about 55k Km on it and it is all covered under warranty.

Supposed to be picking it up today.

Poll 2.5T Coolant Leak/Engine Replacement

 

[ctbale]

Where was the post on the 22 cracked head?

Post 302 says this is a NA CD engine I believe. Not a 2.5t. ?

 

[yrwei52]

Post 302 says this is a NA CD engine I believe. Not a 2.5t. ?

Yes, this thread, cracked cylinder head with oil leaking, is for the 2.5L NA with CD. Cracked cylinder head on 2.5T will have coolant leaking, not oil leaking.

 

[sm1ke]

Yes, this thread, cracked cylinder head with oil leaking, is for the 2.5L NA with CD. Cracked cylinder head on 2.5T will have coolant leaking, not oil leaking.

Just to help avoid future confusion, I'm going to edit the thread title to make it easier to reference.

 

[ctbale]

Just to help avoid future confusion, I'm going to edit the thread title to make it easier to reference.

Maybe put Non-Turbo also? I think I was confused too. Haha. Putting CD in the title would really mess people up considering 75% don't even know they have it

 

[Flight200]

Are most of those cracked cylinder heads showing up before the powertrain warranty expires?

 

[yrwei52]

Are most of those cracked cylinder heads showing up before the powertrain warranty expires?

Not really.

 

[kdaug]

Since my NA, 2.5 CX-5 with CD is a 2018 model I dropped into my local Mazda service department today (here in Canada) to enquire about cracked heads on 2018-2021 NA 2.5L CX-5's with CD and if they had replaced any. I was surprised when the service manager told me that they had replaced between 20-25 of them in the past 2 or 3 years (I hope I heard that right). He went on to say that he vaguely recalls that nearly all the Mazda NA 2.5 vehicles on which they had replaced heads, had suffered leaking oil from the right rear of the engine., and many owners had smoke coming into the car.

He didn't comment on whether they were all on CX-5's but he did agree that he was aware that other 2018-2021 Mazda models with the 2.5L NA engine, with CD were on the list of potentially having cracked heads.

He also commented that his earlier info from Mazda Canada included a range of VIN numbers that could have cracked head problems but today he noticed that there was no longer any reference to a range of VIN numbers and he agreed with my comment that possibly ALL 2018-2021 2.5L, NA, CD vehicles could now be included in this group that could potentially develop cracked heads.

He went on to say that at least 2 of the 2.5T models had come in for cracked head issues. I told him about the 2 main suspected causes as discussed on this forum (poor head casting and/or over torquing of the manifold bolts) and he said that their mechanics suspected that it may be casting issues although he hadn't heard anything official from Mazda Canada on the cause. He did suggest he found it hard to believe that ALL NA, 2.5L Mazda's with CD could have head casting problems, otherwise they would have had more in for replacement, particularly those with high mileage but still within warranty.

 

[ctbale]

Well if this dealer has replaced 20-25 heads on 2.5 NA CD engines that were built after 2018...... I think thats a weakness that all of them have.

 

[yrwei52]

Since my NA, 2.5 CX-5 with CD is a 2018 model I dropped into my local Mazda service department today (here in Canada) to enquire about cracked heads on 2018-2021 NA 2.5L CX-5's with CD and if they had replaced any. I was surprised when the service manager told me that they had replaced between 20-25 of them in the past 2 or 3 years (I hope I heard that right). He went on to say that he vaguely recalls that nearly all the Mazda NA 2.5 vehicles on which they had replaced heads, had suffered leaking oil from the right rear of the engine., and many owners had smoke coming into the car.

I guess I don’t understand why you limited the MY range between 2018 ~ 2021 on cracked cylinder head problem from 2.5L NA with CD?

Mazda has never claimed they updated the head for the 2.5L NA with CD. If you have potential cracked head problem from MY 2018, you’ll have the same potential problem from MY 2023 given enough time and mileage because the cylinder head is still the same. In fact, post #302 above is a recent case of a 2022 CX-5 2.5L NA with CD which had cracked cylinder head. There’s a YouTube video showed the 2 mm thin wall where it’s cracked at the back side of the head. IMO Mazda modified the cylinder head from original 2.5L NA without CD to accommodate bigger switchable hydraulic lash adjusters (HLAs) and compromised the strength of certain areas. The potential problem will always be there unless Mazda would make an effort to enhance the strength of the cracking area on cylinder head.

He went on to say that at least 2 of the 2.5T models had come in for cracked head issues. I told him about the 2 main suspected causes as discussed on this forum (poor head casting and/or over torquing of the manifold bolts) and he said that their mechanics suspected that it may be casting issues although he hadn't heard anything official from Mazda Canada on the cause.

Where did you get this “the 2 main suspected causes as discussed on this forum (poor head casting and/or over torquing of the manifold bolts)” on the cracked head for the 2.5T? Mazda has issued a TSB on cracked cylinder head problem for the 2.5T, and it said clearly the reasons why the crack happened due to the poor design. Mazda has since updated the cylinder head and exhaust manifold gasket after June 2020 to fight against the crack.

The TSB states:

DESCRIPTION
Some vehicles may have coolant leaks at the cylinder head around the exhaust manifold (as shown below). There may be cracks at the stud bolt hole (1) or at the outside of the exhaust manifold flange (2) on the cylinder head.

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 production 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.

TSB No.: 01-002/23 Coolant Leaks at Cylinder Head

 

[CX5Nut]

Since my NA, 2.5 CX-5 with CD is a 2018 model I dropped into my local Mazda service department today (here in Canada) to enquire about cracked heads on 2018-2021 NA 2.5L CX-5's with CD and if they had replaced any. I was surprised when the service manager told me that they had replaced between 20-25 of them in the past 2 or 3 years (I hope I heard that right). He went on to say that he vaguely recalls that nearly all the Mazda NA 2.5 vehicles on which they had replaced heads, had suffered leaking oil from the right rear of the engine., and many owners had smoke coming into the car.

He didn't comment on whether they were all on CX-5's but he did agree that he was aware that other 2018-2021 Mazda models with the 2.5L NA engine, with CD were on the list of potentially having cracked heads.

He also commented that his earlier info from Mazda Canada included a range of VIN numbers that could have cracked head problems but today he noticed that there was no longer any reference to a range of VIN numbers and he agreed with my comment that possibly ALL 2018-2021 2.5L, NA, CD vehicles could now be included in this group that could potentially develop cracked heads.

He went on to say that at least 2 of the 2.5T models had come in for cracked head issues. I told him about the 2 main suspected causes as discussed on this forum (poor head casting and/or over torquing of the manifold bolts) and he said that their mechanics suspected that it may be casting issues although he hadn't heard anything official from Mazda Canada on the cause. He did suggest he found it hard to believe that ALL NA, 2.5L Mazda's with CD could have head casting problems, otherwise they would have had more in for replacement, particularly those with high mileage but still within warranty.

Interesting! I am surprised the Service Manager said anything! Usually if you ask the service dept if they have ever seen a particular issue whey will say no! or you're the first one! I'm going to ask my service dept the same question next time I'm there and see what they say.

 

[kdaug]

I guess I don’t understand why you limited the MY range between 2018 ~ 2021 on cracked cylinder head problem from 2.5L NA with CD?

I suspect that the only years for which my dealer has replaced heads is 2018-2021....so far.



Where did you get this “the 2 main suspected causes as discussed on this forum (poor head casting and/or over torquing of the manifold bolts)” on the cracked head for the 2.5T?

The reference I was making here was not the proof of what has caused the heads to crack but what some followers on this forum have suspected, whether it be for the non-turbo or turbo models.

See post #245 in general. Reference to over-torquing of the manifold bolts is mentioned in posts #35, #79 and #81, and
Implied/discussed possible casting issues can be found in posts #136, #150, #159, #251, #253, #254, #255, #258

You reference that Mazda says that:
Cracks may be caused by (amongst 2 other possible reasons):

• "Residual stress generated during production in the cylinder head material may be greater than expected".

This sounds like a possible over-torquing issue to me.

 

[Flight200]

Does the issue have anything to do with cylinder deactivation?
I just heard that, due to supply chain issues, vehicles built in October and November 2023 will be missing cylinder deactivation and the iStop auto start/stop. The window sticker will show an MPG decrease on the affected vehicles.
If that also solves the cracked cylinder head issue, I might jump on that and buy a CX-5 manufactured during this time window.