Dead At 30K Miles!? Mazda Skyactiv-G 2.5 CX30 Core / Blown Engine Teardown

I finally get to learn what Sky Active really means! It’s been a myth amongst us for years 🤣

Mazda tech here. The Sky-Activ family of engines generally really reliable. In several years of being a tech at a dealer I can count how many full engines we have had to replace. Typical issues you will see with the 2.5L non-turbocharged engines will be a timing cover leak, but most often this will be covered under warranty. The 2.5L turbocharged engines occasionally get a cracked cylinder head, but these aren't too common. One thing to note about the Sky-Activ head gaskets, the head gaskets are stainless steel, and the heads or the block of the engine will usually fail before the head gasket does. They are easy cars to work on compared to most manufactures, and a great car for someone who would like to work on it themselves. They still do have transmission dipsticks (they are small, under the airbox), but its more than just about any other car manufacturer can say. Not really any specialty tools are needed for basic maintenance.

when a mechanic says this engines are hard to find you know that is good.

I was a Mazda master tech here in California, I retired a few years ago. I can remember getting a lot of bad mouthing from the Subaru guys telling me how crappy Mazdas are. The reality of it was our Subaru shop had at least six guys working on Subaru engines at any given moment while us Mazda guys did maybe one engine per month and sometimes less than that. We did have a rash of water pump belts that broke causing catastrophic failure but usually the failures I had witnessed were due to lack of maintenance. I have five Mazda vehicles including a 91 LE pickup that's as reliable as it was when it was new, the only thing I've had to do to it has been just maintenance.

24 yr tech here and those engines are pretty much indestructible never torn one apart so thank you for the insight

Been waiting for this one! I’m coming up on 400,000 miles on my 2015 Mazda 6 and I’ve never owned a more reliable car. Still runs and shifts great and still getting 33 mpg on the hwy. Beside a belt tensioner and an LCA, I’ve done nothing to this car except change the oil every 5K and drain and fill the transmission every 75K. I bought it used with 90K and it’s very comfortable and nimble. I will not hesitate to buy another one when it’s time.

The Mazda Skyactiv engine line will be ones to remember. Long live Mazda!

As someone who isn’t a Mazda fan, I am very impressed by this engine. Some engineering team took their time to build a very good engine. Maybe I’ll have to consider Mazda when buying my next vehicle.

Not an engineer nor have i teardown any engine. But i've seen many engine teardown and this is one of the simplest engine i've seen. No wonder why Mazda engine are so reliable. Simplicity is reliability.

So much more respect to this guy after he named all the cool Mazda's he's owned

As a former dealer guy for ~6years, they have a incidence, low, but every dealer will see a couple, of porous/microcracking of head castings. 99.999% sure that is what happened here. MazdaTSB 01-013/21 Engineering of the SkyActiv family of engines is superb, as is, generally, quality control. Very premature drive belt failure is critical. Fortunately the water pump has its own belt, but AC and Alt belts never make 50K miles. Replace them before that or face a tow in.

My first car was my grandfathers 1986 Mazda 626 with a 5spd manual. He bought it brand new and rarely drove it. We inhereted it when he passed away in 2001 and it only had 18,000 miles on it. Loved that thing!

My mom bought a 2022 CX-5 with the 2.5 liter N/A Skyactiv-G motor and I have to say it’s a very nice little car to zip around in. Aside from the overall good aesthetics and build quality inside and out the drive train and handling are great. Not the most powerful engine but always willing to run and it’s probably one of the only cars in its class that doesn’t get out of shape when the roads turns curvy. Pretty fun package to take on a road trip. Overall satisfying vehicle purchase.

As a long time Mazda driver (literally the past 13 years or so), I’ve been waiting for this. Thank you SO much!

Mazda as a company has remained committed to the ICE, they have not gone EV. They have really pushed ICE technology to get good performance and emissions. I still drive a 2002 Protege 5 I bought new off the lot, 162k miles and still ticking. I'll drive a Mazda for the rest of my life.

I would have to agree these 2.5 skyactive engines are one of the better 4 cylinder options since the late 2010s. No oil burn great fuel economy and a decent amount of power for a lightweight economic chassis. Love the 2.5SA in my 3 with the 6 speed auto. Car feels very complete. 30+mpg with a heavy foot and sGT trim additional weight, best car I've owned in terms of being a "good car".

A relative of mine here in Australia had his fail in a similar manner and it came from the crankcase venting system failing partially open and as the engine works as a partial diesel the crankcase has more blow by than lower compression engines. The oil mist being fed into the inlet manifold led to carboned up piston rings and engine failure through overheat. The inlet ports on your engine all looked wet with oil. I don't know where the crankcase breather feeds into the engine but maybe it favors 3 and 4 cylinders. This same problem was found on quite a few of the first series of four cylinder high revving turbocharged direct injection diesel pick up engines around 2009 to 2013 here before manufacturers got on top of it.

A very simple and elegant engine design. Very refreshing to see after that BMW HOT-V N63 teardown. BMW could learn a few things from Mazda about engine design.

These engines drive so nice for only 186/194 horse power. They make almost all there peak torque from 2k rpm to 4k rpm. During normal driving it feels really nice. You can take big hills even without having to downshift.

Have a first generation skyactiv Mazda 3 hatch, had it for 10 years at this point and it’s been impeccable. Driven 140k at this point with zero issues, definitely became a big Mazda fan over the years.