2.5L NA Cracked Cylinder Head with Oil Leaking

[GTXT23]

I've just run across this forum and wanted to add my two cents. In this case it was more like $5000.00. Towards the end of November, I too started having a burning oil smell in the passenger compartment. This was for my 2018 CX-5. I brought the car in to my repair shop and they diagnosed it right away as a leaking cylinder head. The car didn't quite have 70K miles on it at the time. The nearest Mazda dealer is 45 minutes from me and I was not about to drive that distance with noxious fumes, so my trust auto repair shop would take care of the repairs. The sent the cylinder head to a machine shop actually close to the Mazda dealership. Before they flattened the head, they did a pressure test and discovered that the cylinder head was flawed at the time of casting the part. So my $4000 repair jumped up to $5000. The repair shop found no recalls, but I went ahead with the repairs. I received my vehicle back on December 11. And then started my phone calls to Mazda.

In all I made 16 phone calls to Mazda, later on adding emails with detailed information about my case. All the customer service reps started with the same song and dance about not using the Mazda dealer repair shop. My argument was two-fold: 1) did they want me to risk my health inhaling those dangerous fumes, and 2) the same machine shop the Mazda dealer would have used determined that that part was incorrectly cast, so it wouldn't matter who did the repairs. The faulty part was the faulty part

Eventually the case was bumped up to a case manager, who took a number of weeks to finally get back to me after multiple calls. I should add that I started keeping a detailed log on a Word document, of who I spoke to, the date, the time, and what was said. This proved invaluable. At the end of January the case manager said that she did not think Mazda would be able to help due to the lack of dealer issue again. I went through my case once more, hitting on those two points above. We were speaking on the phone at this point. She told me she would check with her higher ups to see if they could do anything. Imagine my surprise when later that day I received a call from the case manager telling me that they would cover half of the cost of repair, so $2500. I was thrilled. The car was out of warranty, and yes, this is their fault, but I never really thought they would come through. The check arrived yesterday.

As I told nearly everyone I spoke with, I was never nasty, never cursed, and was very patient. I think that paid off. As did my detailed log that I sent to the case manager.

Mazda really should do a full recall on this issue, but I'm happy to have gotten something out of them.

Great news ! -Congrats on persistence ---
The first thing I thought was the same -- have a Mazda dealer that you do business with and trust diagnose the issue -- But This shows Mazda standing behind their vehicles which they have done for me on very minor stuff -- but still-
To anyone reading this with a Mazda- under 36K / 3 years -- consider the Mazda VSA - They have a 125K mile / 10 year ( warranty -VSA - whatever -its the same thing ) with a zero deductible or $100 deductible- There are three levels - Platinum , Gold and Powertrain - depending on your concerns - at least the Powertrain -- I go for the Platinum which effectively covers it all and towing -- -- They covered a leaking Strut , Engine mount , power seat track issue all 100% on an older Mazda I purchased in 2010 and still have --Dealer was happy to do the work -- The reason I suggest this is for about 1/2 cost of your repair $2500 ( thats the platinum 0$ deductible ) you can grab this VSA- The cost is negotiable from F&I so you need to try making a good deal with the F/I person -- Its fully refundable if you sell the car or IF the new owners wont cough up the extra value--get your $$ back-- I think its transferable 1X only -- Mazda VSA will pro-rate a refund -- Glad its running ! Whats the new warranty on that work 12k/ 1 yr ?

 

[walt]

I recently had a similar experience with Mazda Canada for an unrelated, out-of-warranty drivetrain issue on my 2018 CX-9. Initial denial and lots of pushback since my vehicle was out of warranty and never serviced at a dealer, but I continued to plead my case without being overly aggressive or demanding. In the end, a Mazda dealership performed the repair using brand new OEM parts, and Mazda Canada covered almost half of my repair bill. The whole process did take almost 3 months from start to finish, but once the management team got involved, everything moved a lot quicker.

Can you describe the drive train issue briefly?

 

[sm1ke]

Can you describe the drive train issue briefly?

Sure. My rear diff failed about one year after my powertrain warranty expired. They replaced the entire rear differential assembly with brand new OEM parts.

For a more detailed overview of the issue and repair, you can check out my "build" thread.

 

[Luny421]

I created an account here just to share my recent experience. I have a friend that works on the finance side at a Hendrick Mazda dealership. I've bought cars from him in the past where's he's told me he can get any vehicle from the Hendrick network of dealerships. I came across a 2018 Mazda 6 Signature with just under 47k miles at a Hendrick Lexus dealership in SC. Obviously, being at a dealership 5+ hours away, I wasn't able to have a pre-purchase inspection done by my trusted mechanic but it had a clean CarFax with 2 previous owners, the first of which was a lease. I purchased the car on 04/01/25 and took delivery on 04/04/25. I changed the oil the following weekend (04/12/25) and found the oil filter covered in oil and barely hand tight. I chalked the leaking oil up to the loose filter. I had scheduled an inspection with my mechanic for 04/18/25 and told him about the filter being covered in oil. Upon inspection, he found the entire rear side of the motor covered in oil and said it appeared to be leaking from the valve cover, timing cover, and possible the bottom of the turbo, but that it would take a few hours of teardown to confirm if the turbo was leaking. I immediately called my friend at the dealership, told him what was going on, he said to bring it in and they put me in a loaner.

the following morning I got a call from the service advisor. She said they cleaned the oil off the motor, added some dye and found that the oil was leaking from a cracked cylinder head. She said there was a warranty extension that covered this issue, but that the part was on a national backorder until September. Reached back out to my friend, he said they were trying to see if another local Mazda dealer had one, and luckily they were able to locate one about an hour away. This was all on Saturday. The following Tuesday, 04/22/25, I got a call from the service manager, who said that the warranty claim was kicked back and denied by Mazda, as the warranty extension only covered the cracked cylinder head for a coolant leak, not an oil leak. I was quoted $7000-7500 for repairs. I called my friend, he said "don't worry, we'll take care of it". At this point, they had already obtained the cylinder head from the local dealership. A couple of days go by with no word, so I reached back out to my friend, he said they had already started working on it and that it should be ready by the weekend. I was shocked as I had not authorized $7000+ repairs. He said "no, we're taking care of it". I was shocked. Sure enough, I got a call on Saturday 04/26/25 that my car was ready. I showed up and got a receipt for $0.00 owed.

I really like this car, but have lost all confidence in it. I may look at trading it in the near future, likely for a newer Accord. Just wanted to share my experience with Mazda's 2.5L turbo.

 

[walt]

I created an account here just to share my recent experience. I have a friend that works on the finance side at a Hendrick Mazda dealership. I've bought cars from him in the past where's he's told me he can get any vehicle from the Hendrick network of dealerships. I came across a 2018 Mazda 6 Signature with just under 47k miles at a Hendrick Lexus dealership in SC. Obviously, being at a dealership 5+ hours away, I wasn't able to have a pre-purchase inspection done by my trusted mechanic but it had a clean CarFax with 2 previous owners, the first of which was a lease. I purchased the car on 04/01/25 and took delivery on 04/04/25. I changed the oil the following weekend (04/12/25) and found the oil filter covered in oil and barely hand tight. I chalked the leaking oil up to the loose filter. I had scheduled an inspection with my mechanic for 04/18/25 and told him about the filter being covered in oil. Upon inspection, he found the entire rear side of the motor covered in oil and said it appeared to be leaking from the valve cover, timing cover, and possible the bottom of the turbo, but that it would take a few hours of teardown to confirm if the turbo was leaking. I immediately called my friend at the dealership, told him what was going on, he said to bring it in and they put me in a loaner.

the following morning I got a call from the service advisor. She said they cleaned the oil off the motor, added some dye and found that the oil was leaking from a cracked cylinder head. She said there was a warranty extension that covered this issue, but that the part was on a national backorder until September. Reached back out to my friend, he said they were trying to see if another local Mazda dealer had one, and luckily they were able to locate one about an hour away. This was all on Saturday. The following Tuesday, 04/22/25, I got a call from the service manager, who said that the warranty claim was kicked back and denied by Mazda, as the warranty extension only covered the cracked cylinder head for a coolant leak, not an oil leak. I was quoted $7000-7500 for repairs. I called my friend, he said "don't worry, we'll take care of it". At this point, they had already obtained the cylinder head from the local dealership. A couple of days go by with no word, so I reached back out to my friend, he said they had already started working on it and that it should be ready by the weekend. I was shocked as I had not authorized $7000+ repairs. He said "no, we're taking care of it". I was shocked. Sure enough, I got a call on Saturday 04/26/25 that my car was ready. I showed up and got a receipt for $0.00 owed.

I really like this car, but have lost all confidence in it. I may look at trading it in the near future, likely for a newer Accord. Just wanted to share my experience with Mazda's 2.5L turbo.

I does seem ridiculous that Mazda discerns between an oil or water leak. Neither should happen at such low mileage. A cracked head is a cracked head. Especially when there are soooo many. I too am trying to offload my CX5. Thanks for the report.
Just got mail today and got a card for class action suit for defective
infotainment system for my 2020 CX5. 'Limited Warranty Extension'. Why is it Limited. Are they gonna warranty a known problem or not? Our radio drops out and the LCD display goes dim.

 

[austinsho]

These recent posts are really telling. I no longer feel alone about my tale of the leaky 2018 CX-5. But I was wondering...how long did this issue go on? I know the TSB covered 2018-2020, if I remember correctly. Does that mean that purchasing a 2021 and up is completely safe?

 

[Luny421]

These recent posts are really telling. I no longer feel alone about my tale of the leaky 2018 CX-5. But I was wondering...how long did this issue go on? I know the TSB covered 2018-2020, if I remember correctly. Does that mean that purchasing a 2021 and up is completely safe?

In my research over the last few weeks, Mazda made a change to the cylinder heads in August 2020, so in theory, anything manufactured after that shouldn’t have an issue. According to Mazda, it was a combination of design flaws and casting defects.

 

[austinsho]

Thanks so much for the update. It's just obscene that it took three years of faulty production to get it fixed.

 

[Nevada CX5]

My 2018 had a cracked cylinder head. It is total BS they only extend the head warranty on the CX9 and not my CX5. They did provide some financial help but it still cost me $3200. Hoping for a recall...

 

[yrwei52]

.⋯ I really like this car, but have lost all confidence in it. I may look at trading it in the near future, likely for a newer Accord. Just wanted to share my experience with Mazda's 2.5L turbo.

A new Honda Accord? You’d better do some research on problems from that 1.5L Turbo. Although I have a 1998 Honda CR-V with 195K miles which is very reliable, but newer Honda’s is a different story and I wouldn’t want one.

 

[SimpleCanuck]

My 2018 had a cracked cylinder head. It is total BS they only extend the head warranty on the CX9 and not my CX5. They did provide some financial help but it still cost me $3200. Hoping for a recall...

From what I understand, the warranty on the head was extended for those with the turbo engine, which includes the CX-9 and turbocharged CX-5 trims. Your 2018 CX-5 does not have a turbo but does have cylinder deactivation. There is a TSB for replacing that head but no warranty extension.

 

[wlong01]

A new Honda Accord? You’d better do some research on problems from that 1.5L Turbo. Although I have a 1998 Honda CR-V with 195K miles which is very reliable, but newer Honda’s is a different story and I wouldn’t want one.

Also owned a Honda CR-V. First and last. Any prospective buyers should peruse this site:

Honda CR-V Owners Club Forums

Honda CR-V Owners Club forum, the best hang-out to discuss CVT, Hybrids, trim levels and all things CR-V

www.crvownersclub.com

 

[yrwei52]

These recent posts are really telling. I no longer feel alone about my tale of the leaky 2018 CX-5. But I was wondering...how long did this issue go on? I know the TSB covered 2018-2020, if I remember correctly. Does that mean that purchasing a 2021 and up is completely safe?

Some people got confused about cracked cylinder head problem on Mazda’s engines. Mazda has been offering 2 engines on CX-5, a 2.5L NA with cylinder deactivation, and a 2.5T in recently years. Unfortunately both engines suffered cracked cylinder head problem.

The 2.5L NA with CD started in 2018 MY and the head could crack due to the modification to the original head from the 2.5L NA without CD to accommodate CD components. The symptom usually is oil leaks at the back side of the head. Mazda hasn’t updated the head so far which indicates the number of cracked head from this engine isn’t too many within the warranty period.

The 2.5T started in 2016 MY on the CX-9, the head could crack due to the modification to the original head from the 2.5L NA without CD to accommodate turbo components. The symptom usually is coolant leaks at the back side of the head. Mazda has updated the cylinder head and exhaust manifold gasket since 2021 MY, which is supposed to take care of the design flaws on the head. Mazda has also issued a Customer Service Program (CSP11) to extend the limited powertrain warranty to 10 years/120k mi for any owners experiencing the coolant leak.

I believe you have a 2018 CX-5 which has a 2.5L NA with cylinder deactivation. The TSB isn’t applicable to you, and don’t get confused between 2 engines. And this thread is for the discussions of the cracked cylinder head on the 2.5L NA with CD.

 

[SimpleCanuck]

These recent posts are really telling. I no longer feel alone about my tale of the leaky 2018 CX-5. But I was wondering...how long did this issue go on? I know the TSB covered 2018-2020, if I remember correctly. Does that mean that purchasing a 2021 and up is completely safe?

For those with cylinder deactivation, the original TSB covered 2018-2021 models. However, they later updated it to include 2022 and 2023, last I checked. I bought my '22 with CD hoping it would have been resolved, but that was before the updated TSB and I recall at least one instance in this forum of it happening on a '22. I have not checked to see if the TSB has been updated further to include 2024 and newer, and with no indication of whether any replacement heads have failed (last I searched), I will likely trade in my '22 when the powertrain warranty expires. I was planning to downsize to a non-turbo Mazda3 hatch but if head cracks with CD are still an issue by then, I will have to look at another brand unless I upgrade to the turbo which I really do not want (or need).

 

[yrwei52]

For those with cylinder deactivation, the original TSB covered 2018-2021 models. However, they later updated it to include 2022 and 2023, last I checked. I bought my '22 with CD hoping it would have been resolved, but that was before the updated TSB and I recall at least one instance in this forum of it happening on a '22. I have not checked to see if the TSB has been updated further to include 2024 and newer, and with no indication of whether any replacement heads have failed (last I searched), I will likely trade in my '22 when the powertrain warranty expires. I was planning to downsize to a non-turbo Mazda3 hatch but if head cracks with CD are still an issue by then, I will have to look at another brand unless I upgrade to the turbo which I really do not want (or need).

I don’t believe there’s a TSB from Mazda for the cracked head on 2.5L NA with CD yet. The closest one is this Service Alert that covers all the 2.5L NA with CD since 2018 MY.

Service Alert No.: SA-037/23 New Cylinder Head Established

The Service Alert basically helps the Mazda dealers to shorten the labor hours by getting a pre-assembled cylinder head to ease the head replacement. This, IMO, means the cracked head does happen on the 2.5L NA with CD. MNAO gives the dealer the pre-assembled head to save the cost of labor charges submitted by the dealer.

 

[SimpleCanuck]

I don’t believe there’s a TSB from Mazda for the cracked head on 2.5L NA with CD yet. The closest one is this Service Alert that covers all the 2.5L NA with CD since 2018 MY.

Service Alert No.: SA-037/23 New Cylinder Head Established

The Service Alert basically helps the Mazda dealers to shorten the labor hours by getting a pre-assembled cylinder head to ease the head replacement. This, IMO, means the cracked head does happen on the 2.5L NA with CD. MNAO gives the dealer the pre-assembled head to save the cost of labor charges submitted by the dealer.

Thanks for the clarification. That is the document I was referring to, but I confused TSB with service alert.

 

[Luny421]

A new Honda Accord? You’d better do some research on problems from that 1.5L Turbo. Although I have a 1998 Honda CR-V with 195K miles which is very reliable, but newer Honda’s is a different story and I wouldn’t want one.

If I do go the Accord route, I’m only interested in the 2.0L turbo K engine.

 

[walt]

In my research over the last few weeks, Mazda made a change to the cylinder heads in August 2020, so in theory, anything manufactured after that shouldn’t have an issue. According to Mazda, it was a combination of design flaws and casting defects.

Where did you find that info on the date? My door sticker says 7-2-20.
Missed it.

 

[Luny421]

Where did you find that info on the date? My door sticker says 7-2-20.
Missed it.

Got the date wrong, from TSB #01-013/21, it’s for CX-5 & CX-9 produced before June 9, 2020; and Mazda 6 produced before March 25, 2020. This TSB is specifically for the 2.5 turbo and a coolant leak resulting from a cracked cylinder head.

 

[CX5Nut]

What is the real shocker here is that they sold you this car with a cracked head! What, did they expect you not to notice? What a scam!