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

:
2018 CX5
So I have started to see reports of cracked cylinder heads on CX5s (2018-2019) resulting in significant oil leaks. The cars have only ~25K miles on them!
What's this all about? How many here have had this happen? Time to sell our CX5 before it happens?
 
Mazda Corporate is the only place where the actual number of these problems is available, regardless of what any individual unhappy owner says about this being a large scale problem. And I'm sure they keep those numbers under wraps (even from their dealerships), just like every other automaker probably does.

And very few (if any) formal complaints about this problem will have been filed at this point, because the ones happening now are most likely all being handled under warranty at N/C to the owners. So IMO, it's very unlikely that we will find out what the scope of this is, and how many vehicles actually have the leaking head problem - at least while most of these vehicles still have warranties in effect. Not the answer you're looking for, but that's the way it is for just about any of these things, including the cylinder deactivation issues as well.
 
So I have started to see reports of cracked cylinder heads on CX5s (2018-2019) resulting in significant oil leaks. The cars have only ~25K miles on them!
What's this all about? How many here have had this happen? Time to sell our CX5 before it happens??
Like coolant leak problem on the 2.5T, this cracked cylinder head issue on the 2.5L with cylinder deactivation shouldn’t be caused any concerns at this time. Like edmaz said above, only Mazda North American Operations know the true story. I wouldn’t be too worried at this time, especially if my car is within 5-year / 60,000-mile powertrain warranty. But I’d check more often on any sign of oil leak around the engine, and do the UOA more often on the 2.5T for any sign of coolant leak in the drained oil.
 
Good to know. Will be interested to see going forward how many on this board end up having an issue. Hopefully none!
 
Is this the ”report” the OP has seen? A long thread with very few actual examples, but who knows.


My advice - sell the POS before it happens to you!
 
Is this the ”report” the OP has seen? A long thread with very few actual examples, but who knows.


My advice - sell the POS before it happens to you!
That was one of them, and also in the complaint section under "engine" at NHTSA, and a thread at Redditt:

2019 MAZDA CX-5 SUV AWD | NHTSA

2018 MAZDA CX-5 SUV AWD | NHTSA

2019 Cx5 cracked Head : CX5 (reddit.com)
 
To bring back a 3 month old thread, I may be one of the chosen unlucky owner.

2018 CX5 GT, purchased brand new. Current Odo: ~35000 km/~22000 miles. Oil changed every 6 months at Mazda dealership (I live in Canada and it's 8000km/6 months interval).

Last oil change was on Nov 22, 2021. When I dropped it off, I told them I was smelling a strong burning scent in the cabin especially when the fan (heat) is running and the car is warmed up. Also mentioned that I can see smoke seeping out the front immediately after parking and shutting off the car (thanks to the bright headlights). Took a look at the usual places under the hood and under the car, but saw no traces of leak/pooling. They did the oil change and said they didn't see any visible leaks either; recommended to continue driving it and bring it back if the smell doesn't go away.

Fast forward three weeks and I take it back in (Dec 13). They did some digging around and it turns out its from an oil leak. The car dropped/burned almost 1L of oil in the 3 weeks since the oil change. The car doesn't get driven very far/long on a day to day basis and in the past 3 weeks, has only put on about 50-60km/week. Still no pooling on the floor of the garage.

I asked if they knew where the leak was coming from and the technicians had no clue. They took some pictures (my guess with all of the engine plastic off) and now the issue has escalated up to Mazda Canada.

Will update once I hear back once Mazda makes a decision on what to do. Will also ask for the pics they took so I can share that too.
 
To bring back a 3 month old thread, I may be one of the chosen unlucky owner.

2018 CX5 GT, purchased brand new. Current Odo: ~35000 km/~22000 miles. Oil changed every 6 months at Mazda dealership (I live in Canada and it's 8000km/6 months interval).

Last oil change was on Nov 22, 2021. When I dropped it off, I told them I was smelling a strong burning scent in the cabin especially when the fan (heat) is running and the car is warmed up. Also mentioned that I can see smoke seeping out the front immediately after parking and shutting off the car (thanks to the bright headlights). Took a look at the usual places under the hood and under the car, but saw no traces of leak/pooling. They did the oil change and said they didn't see any visible leaks either; recommended to continue driving it and bring it back if the smell doesn't go away.

Fast forward three weeks and I take it back in (Dec 13). They did some digging around and it turns out its from an oil leak. The car dropped/burned almost 1L of oil in the 3 weeks since the oil change. The car doesn't get driven very far/long on a day to day basis and in the past 3 weeks, has only put on about 50-60km/week. Still no pooling on the floor of the garage.

I asked if they knew where the leak was coming from and the technicians had no clue. They took some pictures (my guess with all of the engine plastic off) and now the issue has escalated up to Mazda Canada.

Will update once I hear back once Mazda makes a decision on what to do. Will also ask for the pics they took so I can share that too.
Thanks for the report and please post pictures if you can.

So the 2.5L NA with cylinder deactivation has potential oil leak due to cracked cylinder head; and the 2.5T has potential coolant leak also by cracked cylinder head. I’m glad the 2.5L NA on my 2016 CX-5 hasn’t related to these problems.
 
Thanks for the report and please post pictures if you can.

So the 2.5L NA with cylinder deactivation has potential oil leak due to cracked cylinder head; and the 2.5T has potential coolant leak also by cracked cylinder head. I’m glad the 2.5L NA on my 2016 CX-5 hasn’t related to these problems.
Pics on the Mazda forum under 2018 blown cylinder head thread. Might have made a mistake with this used 2018 cpo.

Two Ford's, a VW, Chevy and Toyota and all engines lasting into 150 k miles plus range and no engine problems.

We'll see what happens.
 
Last edited:
I posted this in wrong thread.

Note here "cylinder deactivation models only"


MC-10202774-0001-page-001.jpg
MC-10202774-0001-page-002.jpg
 
Pics on the Mazda forum under 2018 blown cylinder head thread. Might have made a mistake with this used 2018 cpo.

Two ford's, a VW, Chevy and Toyota and all engines lasting into 150 k miles plus range and no engine problems.

We'll see what happens.
Looks like you like me is thinking long term when we make a car purchase. Most car owners nowadays change cars quite often, once for every 3~5 years so they don’t care the longevity. I bought only 7 new cars in past 36 years, a couple of them were headaches and the worst was my previous 2001.5 Passat GLX 2.8L V6 with 5-speed manual which I special-ordered it. I thought this car would be mine forever as a rare V6 / manual combo. Unfortunately the V6 by Audi was having severe oil consumption issue since new, and VWoA refused to fix it under warranty even though it uses a quart of oil per 800 ~ 1,000 miles! Thus I got rid of it which left me no manual transmission enjoyment with a V6.

I’ve been saying Mazda is going to the wrong direction because they seem to be trying too hard to be different from everybody else with no legit reasons. A first (problematic) cylinder deactivation on an I4 just to save 0 ~ 1 mpg? A turbo been put on a big 2.5L I4 whereas everybody else uses 2.0L with turbo? The SkyActiv-X / SPCCI which is based on good-on-paper-but-hard-to-implement HCCI (thinking the rotary engine) apparently is a failure (at least to me) and big development money spent but can’t sell. I hope Mazda as a small car company won’t need Toyota to rescue them like Ford did it once from all of these major problems which have started popping up due to wrong decisions made by some higher-ranking VPs in recent years.
 
seems like it. Also it seems the 2017 model is with the least of problems in terms of engine issues, drivetrain, etc.
Dont know if you have noticed but they put a lot of $ in marketing. Makes you wonder if they put the same in R&D.
 
So I have started to see reports of cracked cylinder heads on CX5s (2018-2019) resulting in significant oil leaks. The cars have only ~25K miles on them!
What's this all about? How many here have had this happen? Time to sell our CX5 before it happens?
My 2018 CX5 had a cracked cylinder head last year with around 25k miles.

At first Mazda had no idea what it was even though I explained it smells like something is burning when I drive it and smoke would often come from under the hood when I parked.

They sent me home doing nothing the first time, then I called a few months later saying it’s getting worse. They finally said they’ve been seeing this happen with 18-19 models. They kept it for almost 3 months waiting on the replacement head. Luckily I got a loaner and paid nothing.
 
My 2018 CX5 had a cracked cylinder head last year with around 25k miles.

At first Mazda had no idea what it was even though I explained it smells like something is burning when I drive it and smoke would often come from under the hood when I parked.

They sent me home doing nothing the first time, then I called a few months later saying it’s getting worse. They finally said they’ve been seeing this happen with 18-19 models. They kept it for almost 3 months waiting on the replacement head. Luckily I got a loaner and paid nothing.
Thanks... good to know when these are blowing. Got a 2018 cpo which just went over 24k so watching it closely. Sounds like they fixed it before any major damage occured.
 
How much oil did you lose after the May '21 oil change?
I only noticed the smell and smoke coming from the engine bay at the end of Oct/ beginning of November, so there's no reason to believe this was an issue prior to Oct/Nov. In other words, it spat out/burned ~1 L of oil in the 3 weeks time that the oil change occurred and when I brought it back in for diagnostics.

Still no word from Mazda. It's been almost a week now. Not too happy with the speed they are moving on this especially if Mazda North America is already aware of a few affected 2.5L NA, but it is nearing the holidays.

Update: Just got the call. Cylinder head replacement. Crack in cylinder 2. Parts have been ordered, but with the holidays and Covid logistics mess, they can't accurately pinpoint when the parts will arrive and since it's a small leak, they want me driving the car around until the parts arrive. I requested the photos so as soon as I get those I will post.

Update 2: Spoke to the Service Manager just now he's saying it's not a crack, LOL. Service Department can't even get their stories right.
 
Last edited:
I only noticed the smell and smoke coming from the engine bay at the end of Oct/ beginning of November, so there's no reason to believe this was an issue prior to Oct/Nov. In other words, it spat out/burned ~1 L of oil in the 3 weeks time that the oil change occurred and when I brought it back in for diagnostics.

Still no word from Mazda. It's been almost a week now. Not too happy with the speed they are moving on this especially if Mazda North America is already aware of a few affected 2.5L NA, but it is nearing the holidays.

Update: Just got the call. Cylinder head replacement. Crack in cylinder 2. Parts have been ordered, but with the holidays and Covid logistics mess, they can't accurately pinpoint when the parts will arrive and since it's a small leak, they want me driving the car around until the parts arrive. I requested the photos so as soon as I get those I will post.

Update 2: Spoke to the Service Manager just now he's saying it's not a crack, LOL. Service Department can't even get their stories right.
aside from the engine compartment smoke, Did you have any burnt oil on outside of engine/underneath or oil puddles?

Or smoke coming out tailpipe?
 
Back