2018 CX-5 Oil Leak? Is this TSB for Tensioner?

Although I have a very negative opinion of cylinder deactivation, based on multiple other issues, I've seen nothing which connects CD to an oil leak. Information from other threads and sources indicates that there were a batch of heads produced which have manufacturing defects, and are the root cause of some external oil leaks.

If you ask the service advisor who mentioned the cylinder #3 leak, perhaps he/she would confirm a defective cylinder head on your vehicle.
In general I agree that the culprit could be a batch of bad cylinder heads be produced. But the cylinder head used on 2.5L with cylinder deactivation is different from the one for non-CD 2.5L, and it could make some ill-effects when Mazda re-designed or modified the previous cylinder head for additional and different components used by CD. I’d say the problem can be CD related. We’ll find out when NHTSA posts the related documents for more details.
 
I feel kind of sad that I have such a problem with my 2019 CX-5 GT, and it only has 21,500 miles on it. Even though it’s covered by warranty, but still...I always take good care of it. Now, I feel like selling it or trade it in for a different brand crossover. It really makes me lose faith with Mazda.
 
I feel kind of sad that I have such a problem with my 2019 CX-5 GT, and it only has 21,500 miles on it. Even though it’s covered by warranty, but still...I always take good care of it. Now, I feel like selling it or trade it in for a different brand crossover. It really makes me lose faith with Mazda.
If I were you with the same experience I’d be upset too. Nothing wrong with that.

I used to be a loyal VW customer and bought 3 new VWs along the way (I always keep my cars for as long as I can, and buy new car once for many years). The last VW, a 2001.5 VW Passat GLX 2.8L V6 with 5-speed manual, had severe oil consumption issue, 1 quart of oil per 800 ~ 1,000 miles, since new, and VWoA refused to do anything under warranty, claiming it’s normal. I swore I’d never buy another new VW on VW forums, and I did.
 
And with so little driving because of C-19, the warranty will be long expired when the engine blows and we will be stuck with a huge bill. Has anyone else with a non-diesel had their head gasket blow?
 
I found the TSB which related to what I am experiencing.

https://static.nhtsa.gov/odi/tsbs/2021/MC-10194765-0001.pdf

NHTSA ID Number: 10194765

Manufacturer Communication Number: SA-031-21

Summary

A new cylinder head assembly for service parts has been newly established for SKYACTIV-G 2.5 with cylinder deactivation when replacement is needed. Valves, valve springs, valve spring seats, and cotters (IN/EX) are included in the new assembly. DUE TO A SUPPLY ISSUE FOR CYLINDER HEADS, GASKET SETS, AND PARTIAL ENGINE, PLEASE CONTACT HOTLINE FOR REPAIR GUIDANCE.
 
I found the TSB which related to what I am experiencing.

https://static.nhtsa.gov/odi/tsbs/2021/MC-10194765-0001.pdf

NHTSA ID Number: 10194765

Manufacturer Communication Number: SA-031-21

Summary

A new cylinder head assembly for service parts has been newly established for SKYACTIV-G 2.5 with cylinder deactivation when replacement is needed. Valves, valve springs, valve spring seats, and cotters (IN/EX) are included in the new assembly. DUE TO A SUPPLY ISSUE FOR CYLINDER HEADS, GASKET SETS, AND PARTIAL ENGINE, PLEASE CONTACT HOTLINE FOR REPAIR GUIDANCE.
Nice find. This Service Alert #SA-031-21 issued on 5/6/2021 is only for “New Cylinder Head Established” and is a latest several updates to the previous SA-058/20 published since 7/24/2020. Like I mentioned before, it mainly created a new part number with pre-assembled cylinder head with valves to save the installation time. Now apparently there’s supply issue on parts, so whenever there’s a need to replace cylinder head such as cracked cylinder head on 2018 ~ 2020 SkyActiv-G 2.5L with cylinder deactivation, the tech needs to contact Mazda hotline for “repair guidance”.

Nothing new here.
 
.... Has anyone else with a non-diesel had their head gasket blow?
With the goal of having this site be as accurate and reliable as possible, I'll mention that there's no indication at this time of a systemic head gasket issue with our CD engines. There have been various reports of a cylinder head manufacturing issue, and the post below from the 'other' CX-5 forum seems to come from a legitimate source, and sounds like it's on the level (to me anyway). And although 'blown head gasket' does appear elsewhere in that thread, I'd expect a defective head that cracks to very quickly cause the gasket to fail as well. And that's where I'm at with this right now.

I'm not writing this to nitpick your post, only that blown head gasket can conjure up a number of other possible causes, such as head bolts loosening up. So it would not be helpful IMO for this to acquire the name 'blown head gasket issue', when there's nothing concrete to indicate that it really is. However, I also say 'at this time', and certainly don't want to rule it out either. I'm always prepared to change my opinion, if new reliable evidence shows up.

Be advised that if you read the entire thread below, you will have to wade through through a bunch of garbage posted by an idiot who runs amok on that forum (and who is the reason I don't spend much time over there).

https://www.mazdaforum.com/forum/ma...-cylinder-head-gasket-45796/page4/#post195668
 
I agree, me saying head gasket blown isn't accurate. I don't feel concerned about longevity, probably because it hasn't happened to me yet. I checked my filter from the last change, there were a few micro particles of metal in the filter so my car isn't fully broken in yet.
 
For those who had experienced this blown cylinder head oil leaks issue, Please call Mazda customer experience to report this issue. The corporate will not declare a factory recall or mandatory fix if no one reporting this issue. Do your part if you love this Brand and want Mazda to success in the future.

Mazda Customer Experience: +1-800-222-5500, or Online Chat with them.
 
Not only that, if you have an oil leak from a cracked cylinder head, please file a complaint with NHTSA:

They can force MAZDA to do a recall or other measures to make things right for the owners.
 
Not only that, if you have an oil leak from a cracked cylinder head, please file a complaint with NHTSA:

They can force MAZDA to do a recall or other measures to make things right for the owners.
I submitted my complaint already. This is also a safety concern for other Mazda users. This issue can cause fire, accident, or even fatality. I hope they will look deep into it.
 
Last edited:
Spoke to the service manager today for a brief update on my vehicle. He stated that reason Mazda having this oil leak issue is because the casting of the cylinder head wasn't doing correctly. And it creates a hairline type of leak on the cylinder head. The fix is they have the revised version of casting head to reinstall to the engine. He said Mazda have noticed about the issue and it may only affected small batch of CX-5.
 
Spoke to the service manager today for a brief update on my vehicle. He stated that reason Mazda having this oil leak issue is because the casting of the cylinder head wasn't doing correctly. And it creates a hairline type of leak on the cylinder head. The fix is they have the revised version of casting head to reinstall to the engine. He said Mazda have noticed about the issue and it may only affected small batch of CX-5.
Thanks for the update. Are they still waiting for the new head? Hope you have a loaner to drive.

So Mazda revised the cylinder head to the modified cylinder head for cylinder deactivation? I don’t know how much that service manager really knows the true story of the cracked head. But if what his saying is true, it should affect large quantity of engines, not just “a small batch” IMO.
 
I went into the shop area and took some pics. Service manager located where the oil leaks for me.
IMG_20210915_153755-1.jpg
 

Attachments

  • IMG_20210915_153737-1.jpg
    IMG_20210915_153737-1.jpg
    116.1 KB · Views: 246
  • IMG_20210915_153744-1.jpg
    IMG_20210915_153744-1.jpg
    111.7 KB · Views: 232
  • IMG_20210915_153749-1.jpg
    IMG_20210915_153749-1.jpg
    119.7 KB · Views: 255
Last edited:
I went into the shop area and took some pics. Service manager located where the oil leaks for me.
View attachment 303047
Thanks for the pics. I was surprised to see the dealer actually had to remove the entire engine and transaxle from the engine bay for the cylinder head replacement. The crack causing the coolant leak seems to be happened on the exhaust port area between Cylinder #2 and #3. Unfortunately most wordings you put on the picture are too small for me to read. :geek:
 
Fantastic pictures. That job is like a million dollars lol. I guess pulling it apart is cheaper than putting in a new engine. Maybe there is a shortage of engines, who knows. The carbon build up doesn't look bad, and your engine is nice and clean.
 
I guess they will reuse the valves and timing chain and everything else, and install them into the new cylinder head and you will have an almost like new engine. You will have to drive it easy at first as it breaks in.
 
I guess they will reuse the valves and timing chain and everything else, and install them into the new cylinder head ⋯
Timing chain、tensioners、guides、and sprockets will be reused, but the new cylinder head comes with valves、valve springs、valve spring seats、and cotters pre-installed to save the labor time:

DESCRIPTION
A new cylinder head assembly for service parts has been newly established for SKYACTIV-G 2.5 with cylinder deactivation when replacement is needed. Valves, valve springs, valve spring seats, and cotters (IN/EX) are included in the new assembly.

DUE TO A SUPPLY ISSUE FOR CYLINDER HEADS, GASKET SETS, AND PARTIAL ENGINE, PLEASE CONTACT HOTLINE FOR REPAIR GUIDANCE.

Service Alert No.: SA-031/21 NEW CYLINDER HEAD ASSEMBLY ESTABLISHED
 
Back