Cylinder deactivation reliability, issues, how when it works

[Kawzak]

I read some other posts on this subject, but I’m concerned when I go to buy a new CX-5. It looks like the trim(s) of the CX-5 may require having this feature. So here goes- how reliable is this function. What other problems does it present. Does anyone here have a CX-5 w/ this feature have higher milage and have had any problems. Do this come on anytime your at idle or low speed operation. I Don’t Want It !!!, but to get the trim level we want automatically has this feature. Any posts/ info would be appreciated.

 

[zx10guy]

Did you see my reply in your other thread? To me, getting a good condition 2024 in the trim level you want is your only option. Or you'll have to accept going to at least the Select level which is what I did for my 2025.

I don't remember the exact parameters of when CD kicks in, but you can see it in action via a display in the infotainment system when CD engages and disengages. Aside from the anecdotal examples of cylinder head issues with CD equipped engines early on and transmission issues, I personally don't like it. Aside from the discussion of temperature differences between active and inactive cylinders, there's the possible issues of blow by, higher cylinder wall/piston ring wear, and piston skirt wear that has shown in other engines torn down with CD from other manufacturers.

I haven't seen many CD type implementations ever not have problems. Honda has had problems. GM has had problems. The issue with Honda and VFM has resulted in some aftermarket solutions that disable CD. With GM and their AFM, there is an aftermarket solution that requires replacement of the lifters and I think cam and possibly some sort of reprogram of the ECU.

 

[N7turbo]

It activates during light cruising.

You won't notice it activating or deactivating. Mazda has made it 100% seamless.

 

[nickswhip24]

I read some other posts on this subject, but I’m concerned when I go to buy a new CX-5. It looks like the trim(s) of the CX-5 may require having this feature. So here goes- how reliable is this function. What other problems does it present. Does anyone here have a CX-5 w/ this feature have higher milage and have had any problems. Do this come on anytime your at idle or low speed operation. I Don’t Want It !!!, but to get the trim level we want automatically has this feature. Any posts/ info would be appreciated.

its a big topic,it is used for fuel efficiency...in time it may be able to be deleted by tune but currently it would require some steps that could hurt if warranty issue's arise-i own one...it's FINE...But i would rather not have it....look into the differences in engine and transmission from non to c/d-why would it make sense to make both from a money standpoint
can't really speak to reliabilty of it yet,others here seem to have had cx-5(c/d) for longer and should have some feedback-glad i got the car if that helps you-didnt want a cvt and liked the non turbo 4 cylinder as opposed to the 3 cylinder turbo options i looked into to

 

[Kedis82ZE8]

Only method I've seen will give you a CEL mode but doesn't appear to cause vehicle to go into limp mode. One would reportedly have to disconnect one of the cylinder deactivation solenoids.

 

[N7turbo]

Only method I've seen will give you a CEL mode but doesn't appear to cause vehicle to go into limp mode. One would reportedly have to disconnect one of the cylinder deactivation solenoids.

Do we know if this actually stops the transmission pendulum? Not that this would stop the clutches from disintegrating, but I'm curious.

 

[georgem44]

Just bought a 2025 CX-5 S-preferred with Cylinder Deactivation.
Concerned with long term reliability of CD. I know this topic has been discussed quite a bit on forum. Hopefully Mazda has perfected their CD system since 2018 roll out.
Would like to hear from owners with high mileage ( over 50K )
Has tyhe CD system on your CX-5 caused any mechanical issues ?
How satisfied are you with overall performance/reliability of the CD system?

Thank You

 

[MrMcE]

I think it is a non-issue for the CX-5 because the engine is tiny and the deactivation periods are very brief. It is not at all like a big 8 cylinder F-150 that deactivates to 4 cylinders for your hours long highway cruising because 4 cylinders is enough to maintain 70mph nonstop.
In the CX-5, you would basically need to be cruising at 50mph on a downhill to see the cylinders going on 2 for any appreciable amount of time. When I'm on the highway with cruise control on at 75, the wind resistance alone seems enough to make the engine need all 4 cylinders to maintain speed- 2 cylinder power doesn't cut it.
Just making a wild guess that for some, the disdain for cylinder deactivation in some part is fueled by understandings of how it had worked in big trucks that have cylinders to spare while sustaining speed. Fretting about cylinder temperature differences in the little CX-5 4 cylinder engine is obsessing over quite a triviality.

 

[BoomerZoomr]

My brother had a Chevrolet truck (with cylinder deactivation) that was fine too, until it wasn’t (at 150K miles) with one spark plug oil fouled due to a bad piston ring.
If the turbo Mazdas don’t have this CD shenanigans, sounds like another good reason to purchase a turbo model.

 

[zx10guy]

Or a Select or base model on the 2025 models still left. Both of these trims don't have iStop or CD with the NA 2.5.

 

[wlong01]

Kinda brings back memories of the Cadillac 8-6-4 from the 80's.

 

[nickswhip24]

I think it is a non-issue for the CX-5 because the engine is tiny and the deactivation periods are very brief. It is not at all like a big 8 cylinder F-150 that deactivates to 4 cylinders for your hours long highway cruising because 4 cylinders is enough to maintain 70mph nonstop.
In the CX-5, you would basically need to be cruising at 50mph on a downhill to see the cylinders going on 2 for any appreciable amount of time. When I'm on the highway with cruise control on at 75, the wind resistance alone seems enough to make the engine need all 4 cylinders to maintain speed- 2 cylinder power doesn't cut it.
Just making a wild guess that for some, the disdain for cylinder deactivation in some part is fueled by understandings of how it had worked in big trucks that have cylinders to spare while sustaining speed. Fretting about cylinder temperature differences in the little CX-5 4 cylinder engine is obsessing over quite a triviality.

hey ...i'm all about positive thinking
can i send you the bill if i come up dirty with a cracked cylinder head or tourqe converter due to c/d,i am learning what i can about skyactive -g engineering...the model i have also uses an egr cooler so mazda has gone to extremes to continue the mpg madness
the temperature fluctuation between active vs. non active cylinders is an issue regardless of engine size,the exhaust header was an issue in past model years