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.

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

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.

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

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.

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.

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.

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

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.

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!

Been driving my 2020 CX3 Sport since bought new and no issues @ 56K miles. Mazda quality shows in quietness of ride, 30 mpg and safety features and paint/finish. Perfect car for a retired couple with no grandchildren.

I have a 2.0 in my 2016 Mazda3. It was perfect at 110k miles, until a Mazda dealer Tech forgot to put oil back into my engine. They replaced it, no charge, but talk about oil starvation.

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

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 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.

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.

We have a 2021 CX-30 with the 2.5L non-turbo. So far - so good. I drove it today for almost four hours on the Autobahn (we brought it to Germany with us) - half of the time being over 100 mph (160 kph). At 180 kph (112 mph), it turns at 3,600 rpm.

I just purchased the 2024 Mazda CX-30's carbon edition Skyactiv®-G 2.5 Turbo .” And have heard great reviews “

Can we take a moment to marvel at Mazda engine tech over the years? The Wankel, tiny displacement K series V6s, the Miller Cycle, the dual and triple rotor turbos, the proposed Amati W12, the compression ignition Skyactivs... I was surprised to see this engine pop up as a teardown, as they (and the modern Mazdas they power) seem to be some of the most low maintenance, robust cars available in the past 10 years. Just make sure you replace rear shocks regularly... Knowing how rental cars are used, I'm going to make an educated guess that the cooling system was punctured due to an impact of some sort and the car was driven until it overheated. The engine was a casualty, not a cause.

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.

My wife and I just replaced our 2015 BMW 428i with the new 2024 CX-30 because the constant maintenance issues with the BMW and high cost of replacement parts. We bought the CX-30 for the very reasons outlined by others:, it is easier to work on, parts cost less, and this is a high quality car. I appreciate you putting out this video so I could see how this engine is put together. It does look easier to work on.

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.

The first car I bought for myself was an '04 Mazda 6. I had it for about ten years and never had a problem with it. It was a great car.

For some unknown reason everytime I see oiling lines I think way back to the old Toyota land Cruiser they supposedly based it on the Chevrolet inline 6 but perfected the weak points and made them better than Chevrolet by adding overhead oilers and better valve seals. That's why I enjoy the teardown it shows the good and gooderer!

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.

My 2023 CX-5 AWD has been great. This has been one of the best 4 cylinder engine cars I've owned. Look forward to putting many, many miles on it.

Have a 2013 Mazda 3 with the 2.0 skyactiv engine. I think Is one of the best engines in the market. It Is responsive, Easy yo work on and reliable af. Mine has 164k on it and still going strong. I recently replace the Valve cover gasket, and inside that engine looks as good as this one.

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".

Very impressed by this engine. Lots of really good engineering here and nothing that is done in some off-the-wall crazy manner. Just good solid design work. Its also a simple engine as well, likely lending itself to the reliability.

I've owned 3 Mazdas, and I'm hoping to make it 4 soon enough. I've rebuilt the FS engine a few times, and all the reasons it was damaged was user error. Mazda is all logic, and that's why I love them dearly. They are a breeze to work on, and you can tell the Engineers are looking out for the mechanic, when possible. My 2.5 had a recall due to a computer issue with cylinder deactivation, took it in, and instead of fixing the issue, they gave me a brand new engine straight off the crate from Japan. They take care of their customers, and do the right thing. I full endorse Mazda, and highly recommend all their vehicles. #TeamMazda

Could be a manufacture defect: head bolt wasn't tightened enough, causing the coolant leak. You'd have to check the head and deck flatness both to know if the head or block are warped.

I have a 2015 Mazda 6 with the 2.5. For a non turbo 4cyl it has balls. The 13 to 1 compression really shows. Close to 70k and no issues.

I own a Mazda6 2020 with 425K miles on it. Been everywhere in USA and Canada without any issues. Best 20k I ever spent!

Since you said it was a rental car, here’s what I suspect: To start, rental companies don’t exactly take good care of their cars (speaking from experience as a former mechanic who used to service these vehicles). They will decline any repairs unless the issue actually hinders vehicle performance. They will decline an oil change unless the oil is practically darker than a black hole or the low oil pressure light comes on. So here’s my theory: The engine ran past the mileage its service was due. (My guess is 12k overdue) In turn, bad oil circulated throughout the engine (and gumming up cylinders 3+4), thus increasing friction. Increased friction equals increased heat. The increased heat stressed out and caused the head or block to warp and in turn, headgasket to leak externally, thus the loss of coolant. No coolant = overheat. Overheat = toasted engine. But other than that, Skyactiv is a tried and true technology if you take good care of it. My parents have a 2021 CX-9 and I have a 2024 CX-30, which we intend to run well over 300k. This is just a theory based on my experience servicing rental cars. Please don’t come at me.

Mazda’s, hands down the best cars out there right now.

I’ve been waiting to see a Skyactiv 2.5! Thanks for giving me a view into the engine that powers my CX5.

Good teardown, I always wanted to see how these engines looked on the inside. They look like a very well designed engine. Thanks. 👍

Cool how the balance cartridge kinda resembles a supercharger, but in the oil pan. 😂

I have over 310k miles on my 2015 Mazda6 non-turbo. Still running strong!!

The SkyActiv motors are really really good. Very impressed with how reliable they are. I feel like not enough people are talking about them

I was surprised being a Mazda fan myself, that you didn't show the M3 hatchback. I had a 2004 manual, quite honestly the most fun to drive of all my mazda's. the MX3 v6 was a fun car too.

Really impressed by how clean the engine was internally, except for the chocolate shake in the pan. Nice to see perfect bearings & crank.

No surprise that a company run by engineers builds a great engine. I've had 3's with the 2l and the 2.5l NA Skyactiv-G's and they were both bulletproof. Easy to maintain, never missed a beat, and always beat the fuel economy ratings. Mazda builds some of the best cars and engines out there, and definitely the best at their price point.

HolyCrap! finally got one of these?! Never thought you would lol. These Engines are AMAZING! Been asking in the comments for years now lol. 2.5T is really great too, despite the recent gasket issues. 140,000 miles on my 2018 CX-9.

30 seconds in and feeling pretty good about my Mazda 2.5 😆 I did a lot of research before buying this car fresh off its first lease, since I tend to hang onto my cars until they're basically undrivable. 4 years and 50k miles later I'm yet to be disappointed. Hopefully it'll stay that way for awhile.

Two issues. The rings are from the exh valve seals leaking oil, issue with the 21s. see TSB. And at 4:29 noon on the exh port the head is cracked. Possibly CD related. Coolant in oil. My guess is it got pulled for cyls 3 and 4 missfire from low compression.

Steve from near Tampa, Florida here. I watch your videos and it reminds me of the days back in the 80s when I worked at a shop pulling engines from cars, tearing the engine down, sending the block out to be bored and honed, then I would rebuild the motor after all new pistons, rings, timing chain, gears, lifters pushrods and an in house job on the heads was done. Recently I have become a fan of the 2GR-FE engine and want one that I can rebuild.

Thanks again, always like your Saturday night shows. I've had three Miatas, currently own a 21 RF GT. The engineering and build quality are impressive and driving the car is a real joy.

Just gonna say, I've got a thing for these little motors. They're just more appealing to me for some reason. They have to get maximum power from a minimal package.

I adore mazda. On my second one now. Love them. Stunning reliability.

love my 2016 Mazda 6 GT with the non turbo SkyActiv, such a reliable engine. Glad I went with Mazda. Currently at 110k miles and rolling along.

I've owned three different vehicles with the Skyactiv-G engine and currently drive a 2022 Miata. At least one was a Mazda 3 with the 2.5 G series engine like you have here. I am very intrigued by this! I love seeing engines I've actually used torn down. After watching the rest of the video, this is how my 2001 Protege from Mazda failed. Overheated (my radiator reservoir burst on the highway and my temperature gauge was maxed before I knew what happened), and the head gasket warped, effectively broke seal, and started pouring coolant into the cylinders.

Some of the 2.2li skyactiv D engines have had head-gasket problems. Might be a similar issue. As for my 1.5 turbo diesel Mazda 2, runs like a dream after 70K. 50-60 mpg (US) and 600-700 miles per tank for $45. That's a gnats hair off electric costs per mile and when prices return to normal, it will be the same and its a $20,000 car, not a $50,000 4-wheeled-hair-dryer. Diesel rules.

Hi Eric… I was browsing for the review of CX 60 recently launched in ME. I’m glad to see such an amazing video. My first car was a 1990 YM Mazda 929 5 speed MT. I never had any problems with that. I was using it for quite long, about 20 years. After that I was using different types. Now I’m planning to go for a CX 60 2.5 Skyactive G RWD AWD. I’m not happy with the options of available trims. Waiting for the new trims to come. Your video helped me to learn more about the Skyactive G technology. Awaiting your next videos… Thanks.

This engine looks exceptionally well made with a lot of thought gone into it's design. It's a shame this engine encountered a trauma so early in it's service life.

Thanks for this teardown Eric. I like many others on here have been curious to see the innards of a Skyactiv engine. Nice to see Mazda banished all the Ford defects of the MZR series. Shows Mazda still has the knowhow when there's no outside interference. I'd love to see you get your hands on a K-series engine. I still have a 323 hatch with the factory 2.0 KF V6. Such a sweet engine that just loves to be revved like crazy.

Hey, thanks for that great video! It confirms for us Mazda fans why we love our cars so much! By the way, looking at that engine, I suspect foul play. We have 2 Skyactiv 3's with well over 100 000 on the clock, and no carbon, no rust, nothing! They are super reliable.

i'm at 335k km on my 2012 2.0 skyactiv and still going strong. very neat teardown

Very interesting, indeed freaky pistons, odd to have sharp edges on top. Anyway, I trust Mazda to know what they are doing. Nearly bought one of these engines in a new CX-5, and researched this engine in depth, so really enjoyed the teardown. As a diesel guy a lot of this engine makes sense now in how it is designed to work, and it's always interesting to see "different" engine designs, you can never know too much.

"i dont know why i do these things " because its fun eric ! and youd still do it even if no-one was there with you , so would i ... thank you for your content

I have a 1995 Miata. I got it shortly before it turned 222,222 miles. 1.8 Rebuilt for boost at 232k. It has just under 239k now. I'll get around to boosting it this winter hopefully. I imagine Mazda is the kind of company that wants a failed engine back for analysis most of the time.

I got suggested this probably because I've been watching a lot of CX-30 videos. Now I'm subbed and bingeing.

Wow, cool to hear about you being a Mazda fan. I've owned 4 1988-89 MX-6 GT Turbo manuals back in the days. Upgraded them to about 250whp and smoked a bunch of cars back in the late 90's and early 2000's. Missed them, still looking to find a nice clean original example.

My sister has a 2013 mazda 3 with over 200k miles. When she got it with 180k she didnt know you had to change the oil and went over 20k without an oil change. Still running strong somehow

a very well done and explained tear down. thanks for showing us. here in NZ we have loads of these on our roads and its great to see how they work. cheers NZ

I work at a Mazda dealer in europe, Cyl4 spark plug IS ALWAYS WET AND LESS TIGHTENED (with a wet thread) than the rest of the plugs, on all the G’s I’ve replaced spark plugs on (a lot). Spark plug replacement at 120k km (iridium ILKR7L11). No issues with engine smothness before or after. Did some compression tests on newer G’s and it’s the same situation. My guess is the automated assembly machine that drives the plugs in looses torque at the 4th plug after doing the former 3 plugs but I don’t know for sure obviously.

Own a 20 CX30 and I will NEVER tear down a 2.5. But it is great to see how well it's built.

The Skyactiv engines are so cool. Inside the intake cam gear is supposed to spin like that because there is a EVVT (Electronic Variable Valve Timing) module that sits in there and will obviously control timing but I absolutely love these engines. So easy to tear down. Great video!

Great video. If I'm not mistaken there should be a tapered plastic sleeve in the cooling jacket around the cylinders to modulate cooling up the cylinder wall and focus it around the combustion chamber. If this is missing, as it appears to be in the video, then the head temperatures could exceed the gasket design.

Mazdas are great cars. I’ve owned many. Usually the only issue is a blown head gasket due to plastic radiator. My current mazda overheated at 267k miles due to thermostat-cracked radiator. I would buy a new Mazda without hesitation.

My sister's 2016 CX5 failed at just under 61k. Head cracked and leaked coolant and oil into the spark plug wells. Out dealer replaced it for free out of warranty because the issue began inside the warranty period.

Really neat little engine. You’ve struck the perfect balance between exploring engine design and relishing in catastrophic damage. The channel just keeps getting better!

I own a 2016 Mazda 6 GT and this is cool seeing someone tear apart this motor. Keep it up!

I have a 2.0 sky active on my Mazda and I love it, iv put it through hell and back and she still purrs every time I start her up ❤️ of course maint. Is always up to date and prev. Maint. Is done regularly.

That was an amazing teardown. I am on my 5 mazda 3 and they are brilliant cars. I have a 2L Skyactiv X in mine and its such a good driving car especially on the motorway. Lots of torque for a 2L.All your teardowns are simply fab. Cheers Mate.

This is awesome (for lack of a better term)! I own a 2019 cx5 with 30k miles and absolutely love the car but it’s crazy to see the engine like this. side note, also a Mazda fan, as a teenager in high school I had the coupe mx6, 1990 was a great fun car to drive!

Had to subscribe because your a fellow Mazda guy. I've always admired them but never owned one until buying my wife a brand new Mazda 6 with this same engine in 2018. Since getting it my collection has expanded to include a '96 Miata, '09 RX-8 bought with just over 7k miles and now just over 15k, '08 Miata and '82 RX-7 derelict I hope to save (have 2 parts cars to go with it). I found your video searching on Skyactiv G because the 2018 after over 107k trouble free miles gave us our first scare with a failing coil pack a couple weeks ago. So as it moves on into aging hooptie territory it's time to learn more about it. This video helped a lot.

"Carnage and debris". Two of my fav words. Really enjoy these tear downs! Thx!

Has anyone else noticed that gigantic turbo sitting on the shelf in the beginning of the video?

finally after many videos of requesting you finally tore one apart. Great video and can't wait to see other engines you teardown

This series is a revelation. I used to think that calling people “technicians” who used to be “mechanics” was a bit pretentious, but I have changed my mind. These things are two whole orders of magnitude more complicated than the engines of the 1970s.

My parents owned a Mazda MPV, 2005 for 19 yrs. Sold it with 225000 miles. Only had a trans rebuild, they never changed the fluid so that was on them. They recently bought a 2021 CX5 with the NA motor. Phenomenal cuv. Great quality, butter smooth, strong enough motor, plenty of room, nice interior, elegant look. And they have the base model. I’m sure it will last them a long time too.

My 2016 Mx-5 is still purring along at 70k miles, absolutely love it. It'll always be my little Red Barchetta, hoping it runs well past 300k. Awesome breakdown, these are great engines!

I used to work at a franchise shop that serviced the rental cars for a company that had a name that rhymed with Enterprise. Not only would people drive the cars like they stole it. But the company wouldn't pay for the required oil grade, also they wouldn't pay for more than 5qt's of oil. So if the car or truck called for 6.5qt's of synthetic 5w30 we would be required to put 5qt's of 5w20 conventional.

Im on 50k on my cx30. Notta one problem. In fact, it's gotta be the best 2.5 I've ever owned, and I typically by Toyotas.

My wife drives a 2018 6 with a 2.5 turbo and it’s great. I’ve flogged it like a beater for 5 years and it’s oil is still clear and no issues with 100k on the odo. Maybe we got a good one, but it’s a fantastically good family hauler.

Even though there wasn't any carnage, it was interesting to see how the Skyactive engine was engineered and built. I have to say I'm impressed. I'm especially impressed with how they managed to run the gear train so simply. Like Elon Musk, I subscribe to the "best part is no part" philosophy. No wonder a previous poster said that the engines are easy to work on. Compare that to one of the BMWs or Audis you have had to tear apart! As usual, a lot of fun. Keep 'em coming!

Very interesting very thorough tear down. Now I almost understand the skyactive. My granddaughter has an M3 and it runs so smooth. Thank you.

New sub! Thanks to the algorithm for dropping your channel in my feed. Greater credit goes to the good content. Look forward to seeing more. Thanks!

Mazda is putting Cylinder Deactivation (displacement on demand/other names) on all non-turbo 2.5 4cyls in recent years, but not for long enough to show high mileage problem trends. Once large numbers of these cars (that have operators whose driving style activates the CD) will see if Mazda does CD/DOD better than others.

2nd gen MX6 was so good, love the sound of that KLDE Also spotted you in the Miata group last night!

This is good to hear and see, I have a 2021 Mazda CX-30 with the 2.5L Skyactiv-G non-turbo like the engine in the video. I hope that the transmission and other components last a long time, recently the cooling fan for the drivers side headlight went out and it costs over $1,000 + labor to replace but it’s covered under warranty. I hope ones the new part is replaced it won’t fail again (my car is less than 2 years old)

Thanks for great overview. Appreciate your work. Own cx5 2nd gen since 2017 and also had 626...it was just great. Happy that mazda decided to use a chain again ...

Really interesting to see the engineering in these engines vs the L3/L5 engines, some similarities (balance cassette) and a few differences. I'm aware of a small number of Skyactive engines going bad prematurely in Australian delivered CX-30's that seemed to expire from an overheat situation, all of them seemed to be around summer 2020-2021 and summer 2021-2022 (high ambient temps and seemingly bad engines from a small VIN number range). If I remember correctly there was a Mzda service bulletin regarding a potentiasl issue around that time and it did get media attention at the time as well.

My sister has a Mazda, CX nine with a 2.5 turbo she loves it.

on our third CX-9, the second one with this engine. have also previously owned an MPV and a 2nd-gen RX-7. this engine teardown was well-executed. for as much abuse as this engine took on, it looked surprisingly in-tact. the current version puts out 250hp and 320lbft torque with full-time AWD.

I own a '16 mazda6, my wife has a '20 CX5, our oldest daughter drives a '10 mazda6. Not a single repair needed. Just maintain and they get you there and back! Cool video, and always wanted to see inside the engine.

Interesting episode Eric!!! What was of particular interest here, was the composite head gasket failure, which was not the only thing that failed.... The head and block are both made of aluminum.... Aluminum typically looses it's tempering at about 475°F. The overheat could have caused the Aluminum in the part of the engine that was the hottest place of that engine to go above the critical temperature of 475°F. And it's possible that the annealed aluminum female threads holding down the head, started to fail and allow a partial release of the down force of the head, being provided by the head bolt(s)... And with a ridiculously high compression ratio of 14:1(for a spark ignition engine), that block should have been made of cast iron like the vast majority of truck diesels are with that high of a compression ratio... If the annealing of the aluminum from an overheat did occur, then this engine is probably a victim of design flaws....Your most interested customer of this engine, just might be Mazda, to see what could have caused this engine of theirs, to fail with only 30k. miles....My guess is either they lower the compression ratio or they control the overheating which was probably caused by detonation, by retarding the fuel burn to begin AFTER TDC by using another program on the direct injection system, THUS REDUCING POWER AND EFFICIENCY...The people at Mazda seem to be pushing the limits with this engine, using diesel engine compression ratios with pump gasoline... The first sign of this engine developing excessive heat, was the use of the two lube rails above the camshafts, to be able to provide lubrication in critical places during extreme heating conditions... And to help carry away the extreme heat build-up on the head... That engine oil pump is HUGE for that little 4-banger... It's purpose goes well beyond lubricating this engine... It circulates BUCKETS of oil to help this thing keep it's cool...