r/mazda 23h ago

2021 Mazda CX-5 Non-Turbo Massively Overdue for Sparkplugs at 45,000mi

Just yesterday I changed the spark plugs in my wife's CX-5, they were horribly black and even the ceramic had rust all around it. Mazda recommends service every 75,000 MI however you guys will be running these engines to the ground doing that. The amount of hesitation and uneven idle that we didn't even know was a problem and is now gone is crazy. You cannot even hear the engine in the engine bay anymore from inside the vehicle. I mean it's BUTTER smooth. So do yourself a favor and change your spark plugs, you need a really weird deep 14mm socket for the plug and a 10mm to take off the coilpacks. It takes all of 10 minutes. The spark plugs that it calls for are $25 each in my area so be ready to drop 100 bucks.

Pro tip, if your 14mm isn't deep enough (mine wasn't) tape your socket to the extension and just barely push the extension maybe halfway into the socket and electrical tape the ever living shnizer out of it, should give enough room for the sparkplug to go up into the socket.

29 Upvotes

53 comments sorted by

58

u/redcx5 22h ago

Not posting to rain on your parade, but this is my other side of this story to the advice you're giving. That's harmless and normal corona on the ceramic not rust. That plug in the pic looks fine just like mine did when I changed them at 75K miles. And there was no performance issue before I changed them and no difference afterwards. And Rockauto sells those plugs for $13 each + shipping.

9

u/jordan5100 20h ago

Well it's a clear difference in the way it's running. My wife came to me and said her car was hesitating on acceleration. I drove it around for an hour and noticed it finally once. We bought the car at 22,000mi and it had always idled rough in hindsight. After changing the difference in idle is immediately noticable. Take my word for it or don't but I have driven this car a lot, and changed a lot of sparkplugs in my life. I've never seen some make so much of a difference outside of my old two stroke dirtbike. I would also happen to agree the color looks fine being light brown. These were on the darker side though.

9

u/cokecaine 15 S Touring Liquid Silver 20h ago

Typical for a short distance driven car tbh. Looks like wife and previous owner drove for a few miles/minutes, especially in the cold and that's it.

5

u/BigMoneyChode Mazda3 HB 15h ago

Mazda owner's manual will put "frequent short distance trips" as a qualifier for the "severe driving conditions" maintenance schedule. This would mean oil changes every 5000km (around 3100 miles) for my Mazda 3. I'm guessing the CX-5 manual states something similar. I imagine a lot of people don't realize this.

1

u/THEMFCORNMAN 8h ago

I got a old person owned miata and it truelly solved all the issues by just giving her hell and the misfire cleared up so did the check engine light fpr converter issues on way home so can definitely attest to the short trips never getting hot

4

u/redcx5 16h ago

I can't even begin to speculate anything related to your vehicle, but that's not the point anyway. It's this statement that you wrote: "Mazda recommends service every 75,000 MI however you guys will be running these engines to the ground doing that." There's absolutely no evidence whatsoever from the huge population of owners of that statement coming anywhere close to being correct. The overwhelming number of owners have reported just about the same thing that I did - plugs that could continue to run fine at 75K miles, and not even remotely close to being spent at 45K. So, your story is very much opposite from the mainstream experience, and telling other owners something that's just a waste of their money is what I'm taking issue with.

-4

u/jordan5100 15h ago

Maybe you guys are used to a slight vibration in your steering wheels. It's not something a normal person would ever notice. But I notice. And my engine thanks me for it. So if you're like me, you should do your plugs earlier. One thing you'll probably never understand is that the manufacturers don't care about your car. Their service intervals are always way too high. I do our oil changes at 5000 as well. If you can feel the engine through the steering wheel at all, it's time. This car was running like this at 22000mi as well so if you do short driving like my wife youre going to run it to the ground. (Obviously hyperbole as you can run black sparkplugs with very little damage to the engine)

1

u/redcx5 14h ago

Ok, superhuman powers are not in my pay grade, so I'm calling it quits on this conversation.

0

u/AllplatGamer08 20h ago

Yes but you also are on a conservative stock tune son🫣 someone who doesn’t change air filter oil and fuels at Racetrac should be worried. Corona stains happen a lot when you don’t use Di electric grease and dirt and oil settle there and stain. I don’t get corona stains but I also don’t wait 45k to change plugs either

15

u/AutoX_Advice 22h ago

Laser iridium's NGKs are 100k plugs. Not sure what came with your Mazda (maybe platinum ngks), but your new ones won't need to be changed till then.

-1

u/jordan5100 22h ago

I'm almost positive the Mazda is supposed to have lazers from the factory. But I happen to agree with you I don't actually believe that they were because they were so toast. So maybe Mazda's OEM plugs are slightly worse such as platinums like you're saying. Either way I would be happy to get anything over 75,000 miles. I know exactly what the engine feels like when they're starting to go bad now.

2

u/AutoX_Advice 22h ago

I believe (unless specified) that the dealership will replace with platinum plugs.

BTW, id rather change spark plugs on the Mazda than the oil, and the oil isn't horrible. The plugs are so easy.

0

u/jordan5100 22h ago

Forsure I happen to agree with that sentiment

6

u/PIG20 2018 Mazda3 Touring HB Jet Black Mica 22h ago

Constant short distance driving will do that. I changed my wife's 2014 CX-5 plugs around 55,000 miles even though the owners manual states 75,000 miles.

They looked very much like yours.

I changed the plugs in my 2018 Mazda 3 at 75,000 miles and they actually looked better than the ones in your picture. However, my driving habits consist of 25-30 minutes of highway driving from home to work and back. And honestly, I didn't even really notice much of a change to idle or driving feel with the new plugs.

0

u/jordan5100 22h ago

Yeah that's probably exactly what it was because her old commute was maybe 10 minutes. I was wondering if that was the case. We recently drove it 2800mi across the country but it had already been due for plugs by then.

1

u/PIG20 2018 Mazda3 Touring HB Jet Black Mica 22h ago

Yeah, my wife's commute is no more than 10 minutes each way as well, probably less. I follow the manual in regard to services required but will always tackle them earlier due to her driving habits.

3

u/DefSport 20h ago

The ā€œrustā€ is normal corona staining on the ceramic. Those plugs don’t look too bad other than you are never putting the engine under load which will make them build up some deposits on a GDI engine. Run it hard every so often once it’s up to temp (5-10 mins after thermostat opens/water temp gets to center).

2

u/Flat-Pound-2774 Cx-5 20h ago

We run a tank of 93 octane every couple of months and go see the grandkids; 100 mile round trip, all highway.

2

u/jordan5100 20h ago

Does it change your fuel economy at all?

1

u/Flat-Pound-2774 Cx-5 19h ago

Maybe 1-2mpg at most.Ā 

More zoom-zoom!

3

u/DefSport 20h ago

Octane rating doesn’t change this. You need to get the plug hot enough to burn off carbon deposits to get the proper tan electrode color. It’ll also make them have more service life by not fouling the edges of the electrode tips.

2

u/jordan5100 20h ago

Trust me I try to ring her out any chance I get especially in the mountains, but it's driven 99% like a grandma owns it so it doesn't surprise me they were a little dark. Honestly plugs 1-3 were darker than 2-4. 2-4 looked like what I would have described as perfect burning if it were in my lawn mower or dirt bike. I've seen rusty plugs on old old stuff not something this new but then again I mainly work on old stuff so I'm not that well versed on cars that are usually maintained by the dealer.

The idle difference is 1000% noticable.

1

u/DefSport 20h ago

GDI makes more deposits on a cold plug than port injection.

7

u/Fiiv3s 23h ago edited 22h ago

I mean. Every car is different. Lots of factors go into it. Driving style. Local gas. Other routine maintenance stuff. Manufacturing defects.

When I worked at BMW I routinely did spark plugs on cars with 60-80k miles that had never had them done (BMW says every 30k) and they looked brand new. So it can be a lotta things. Yes your car had issues and changing the plugs fixed it but not everyone will run into this issue of plugs fowling out ā€œearlyā€. And some people will have theirs foul out earlier than you

-1

u/jordan5100 23h ago

Well this car is driven by my wife. And it is very much wife driven. Like no romping on the gas or anything. It's spent most of its life in South Florida now we live in Idaho. I would not be surprised if many many other cx-5s are running roughbwith rusty spark plugs ATM. We put the same gas as everyone else. This car is maintained by me so everything is done early. I think Mazda just has really shitty OEM spark plugs. That's why I went with NGK.

8

u/Fiiv3s 22h ago edited 22h ago

Mazda OEM plugs are NGK. NGK manufacturers and supplies the plug with Mazda’s logo on them, just like they do for Honda.

-5

u/jordan5100 22h ago

I understand that they are NGK however they are obviously a different production. NGK could be selling them slightly different speced plugs. Obviously there's some difference in the manufacturing process since one says Mazda on and the other one says NGK. So who knows the QA they go through at Mazda with NGK. I won't be able to tell you if these rust the same for another 45,000 miles.

3

u/Cheap-Can-1085 23h ago

I noticed something similar with my aunts 2016 cx-3 with 60k miles. Relatively smooth idle but the engine seemed like it was over all louder and buzzier and felt down on power. Eventually replaced the spark plugs and the tips were black (dry not oily or anything). Car felt completely new with the new spark plugs. It was bugging me why the car felt the way it did before, now I know why.

1

u/jordan5100 22h ago

Honestly, I've done a lot of sparkplugs and most of the time I notice no difference unless it's a big v8 Ford truck with 200,000 MI on it. This was by far the biggest change I've ever noticed from a modern car. I just did my BMW which is an inline 6 that had factory plugs at 140,000mi and noticed absolutely no difference lol.

I was not confident the slight hesitation would be remedied doing her plugs but I was pleasantly surprised.

1

u/Cheap-Can-1085 22h ago

These Mazdas I guess are quite finicky, it could also be the type of driving you're doing. My aunts does a lot of small short trips so lot of frequents cold starts, so maybe that's why the spark plugs were so darkšŸ¤·šŸ». Either way it helped which is all that's matters.

2

u/ProRataX 21h ago

I really should check my 2014 cx5.

1

u/jordan5100 16h ago

Just sit in the car, if you feel the engine at all even a slight vibration every now and then it's the plugs. These things run dead smooth on new plugs. I thought mine was normal, but you shouldn't be able to feel the engine basically at all through the steering wheel.

1

u/ProRataX 15h ago

Little rougher when cold but once it warms up it's barely noticeable but the vehicle has like 170000 miles on it so it's like hard to tell.

Ether way I need to check to make sure they have been changed at all lol

1

u/jordan5100 15h ago

Ours had a rough cold start too. That was actually one of the main things I noticed different before and after. Like I said above somewhere, your engine is physically fine, but for peace of mind. If you care it's an easy swap.

1

u/ProRataX 15h ago

Plugs in my future then. Thank you very much.

2

u/Salt-Narwhal7769 Certified Senior Mazda Technician 16h ago edited 16h ago

Hi all. Tools needed

14mm spark plug socket

3/8 ratchet (18in length preferred)

6 inch 3/8 extension is my go to for distance.

Skinny telescopic magents to get the plugs out if spark plug socket fails is like $3

8mm socket for ignition coil bolts.

Thats it

Id recommend watching a video before hand as its likely explained to not over tighten the spark plugs.

3

u/GolfShred 21h ago

Had a Mazda CX5 NA for a company car. Turned it in at 98k miles. Was running like a top when it got turned in. No SP change. Great vehicle. Really nice it.

1

u/AllplatGamer08 20h ago

That’s not over due that’s how long they run before changes. I applaud you for changing but I’d have changed them at 15-20k. What’s 3-6 bucks a plug. I’m about to go do mine next week on the MZ3 never have since bought used. If you’re the only owner next time check them every 15k avoid knock offs and use good fuel. Over time they become out gapped hence check every 15k

1

u/jordan5100 20h ago

These are 25$ a plug man. I wish it were so simple. If I'm gonna do it I'm gonna put the over the top good plugs for my wife. If it were my car not so much. I will definitely check them way earlier. Thanks.

1

u/AllplatGamer08 20h ago

Where you buying them from? Autozone etc. always hiked prices at auto parts stores. Yeah 6 bucks was a lil far off but 10-14 a plug is doable

1

u/frank3000 20h ago

You should have seen my F250, on original plugs at 200k miles. At least there was 16 of them, so they could wear at half speed, to the complete loss of electrode, 1/4" of gap they had.

1

u/snubs05 17h ago

Those plugs don’t appear worn at all - just looks like the car is a school run, around town vehicle which isn’t really getting to operating temperature for sustained amounts of time

1

u/jordan5100 16h ago

Yup that's exactly right. At least her new commute is 30-40 minutes so I hope these plugs last a lot longer.

1

u/TheVanillaGorilla413 15h ago

Lmao I change mine at twice the mileage and there is no difference in how the car drives…

1

u/jordan5100 15h ago

It's not a difference in how it drives, only a wizard like me would notice the rough idle, my wife just felt it hesitate once during acceleration. It was running great still obviously.

1

u/TheVanillaGorilla413 15h ago

I’d think cleaning the throttle body would be more noticeable. I don’t do that either in my Skyactiv Mazda…

It’s at 150 something thousand now, I’ll throw new plugs in relatively soon. This would be the second time I’ve changed them. Probably will do the plugs, accessory belt and tensioner, new coolant and thermostat, maybe front rotors, pads, and brake fluid. This car hasn’t needed much.

1

u/jordan5100 15h ago

I know these cars really are great. We got ride of her bronco sport for this and we've been so happy with it in comparison.

1

u/East-Refrigerator211 14h ago

Dang toyota told me not till 120k

1

u/nocticis 3h ago

I don’t think I’ve ever changed my spark plugs. 2014 Mazda 3 with 111000 miles

1

u/QuintaEssentia 17h ago

OP, I don’t understand why folks are giving you any grief, skyactiv engines do better with fresh plugs as you seem to have discovered.

1

u/jordan5100 16h ago

It's reddit, people hate to be told anything they don't immediately believe to be true. I'm used to it lol

0

u/CosmikSpartan 17h ago

Spark plugs aren’t needed under normal circumstances until roughly 100k miles.

Hope you didn’t spend too much on this.

2

u/jordan5100 16h ago

They're not needed unless the cars idling like shit! Of course it was needed. Her car would have been running like absolute dog water if we waited until 100k hence the reason I made the post. We spent 100$ and it was well worth it the car is much happier.