Just read about the bad heads on the 18-19 CX 5s related to cylinder deactivation. Did they get that fixed for the 2021 model year? I just bought one off of Carvana with 9,000 miles on it. Now I’m worried it’s gonna blow

 

If it's s turbo, it's probably fine as they redesigned the turbo head.

If it's an NA CD, it's questionable ...there's never been confirmation or TSB that the head was redesigned. It's possible it was a bad batch of heads that were incompletely formed during the manufacture casting process and maybe the process was corrected. But no one knows for sure. Both internal combustion pressure and external pressure(from road travel/bumps) cause it to crack at the defective weak point.

Don't baby it...that will just ensure that it lasts until the warranty runs out then cracks. Run it like you normally would, get the mileage on it(get it up past 40/50k) and chances are it will hopefully crack during warranty. Luckily my work commute pushed the mileage up and my state and local roads are not the smoothest with bumps and potholes that may have helped facilitate the problem instead of it being a hidden defect for years.

Also look into getting an extended warranty. Read the fine print on what's covered.

 

I've never seen any engine issues with cylinder deactivation.

Can you provide any info on your concern?

 

Grim:

TSB is SA-31/21. 10/15/21

Provides info for head replacement on Cylinder deactivation models. But is worded very carefully. Also does not state if head was re-designed only gives part numbers for full head replacement.

Thread on 2018 CX-5 cracked cylinder heads on this forum and Mazda247 forum and reddit.

Will post pics tonight of my leaking 2018 CD behind cylinder 3. my pics clearly show the leak.
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Your car should be fine. It's an issue that seems to have happened to a select amount of people (most likely a bad batch as mentioned earlier). Just keep up with maintenance and the car will treat you happily. These cars are some of the most reliable out there in the market!

 

head crack behind cylinder # 3
Here is pic of crack behind cylinder 3. you can see the oil streaming out of the crack

 

Sorry maybe a poor picture lacking better detail but where is this crack that is pouring oil from? Looks more like a valve cover problem. But I will wait and see what you can clear up?

 

FInd the screw on the valve cover, then look below. Zoom in for clearer view. They replaced the whole cylinder head. Was smoking pretty bad and sparking on top of manifold the night before. Doesn't leak immediately at startup . Need to leave run s minute or two then it's starts streaming out. Was hard to stretch and take pics. And had to be quick before it caught fire. Had it towed to dealer.

 

Hmm I don't see it? I do see a wet valve cover possibly leaking?

 

close cracked cylinder oil leak

Hmmm. Why does your picture of the head look so much cleaner than mine? Something doesn't seem right?
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