Hey all,

I'm getting close to the 50k mileage marker on my 2021 Turbo. I know that Mazda recommends doing plugs at 37.5k miles, but my car still seems to run perfectly fine. I do tend to floor my car often and use premium gas from good quality stations. I've been religious with my oil changes every 5k miles too. I know that the plugs need to eventually get changed, but is it really necessary now if my car runs fine and still gets great gas mileage overall? I have a Mazda dealer that could do it for $350 with no tax (Benefit of living near New Hampshire ). What's your guys' opinions?

 

Yes.
First to be very clear this is not an opinion but can be verified and also we could call it fact even empirical fact supported by simple test and results .
If you were to run an oscilloscope right now on your ignition which excludes your spar plug an and coils and data logged both parts then each cylinder. Then change your spark plugs and run the same test and compared results you would find that your engine is not running as good as it was 16k miles ago.

Do things right, change the spark plugs and also the coil boots . I am confident you will notice a performance difference .

omg 350 bucks are you kidding me … you can’t change spark plugs and col boots dude that’s like 50 dollars or less for parts and 300 labor

 

So this is an easy DIY? I have changed spark plugs in the past and would entertain it on the Mazda. Mine is at 33k so I have a few miles to go. I have not heard of changing the coil boots. Do you use OEM or aftermarket parts? How about for the plugs?

 

Mazda OEM spark plugs are manufactured from aftermarket companies. .
Yes you personally can and should change you own spark plugs.
I think overall it is best to use NGK saves debates.
DO NOT GAP them or attempt to gap them unless you decide to get old style standard or commonly called copper spark plugs. But unless you are racing I cant see the point to use them.
Your choice to use anti seize on the plugs. If applied correctly they offer great thread protection..
The boots are inexpensive and very easy to change. the reason for changing them it to keep the integrity of the sealing of the boot around the top of the sparkplug. There is a spring that rarely gets serviced by DIOY and many service shops. This spring can become less effectively secure on the top of the spark plug or otherwise called the terminal and or stud. The spring can also become dirty or corroded which can reduce the energy to the spark plug from the coil..
Don't forget to properly use and do use during this service dielectric grease.



I personally only apply the grease to the first few threads on the new spark plug

 

Thanks for the write-up. Much appreciated. I will give it a try when I hit 40k.

 

To be completely honest, this is my first vehicle I've ever owned where I actually am at a low enough mileage to have to do plugs LMAO. Any chance you could list the part numbers for the turbo model plugs and ignition coils? It doesn't look too bad so I might try it myself. I think I have enough tools to do it, but I will need to be careful with the bracket above the coil packs.

 

Without having the production date or VIN this is what I found.
LOL don't post your VIN on an open forum...

NGK retail number 90288 or the more familiar number DILKAR7M8
Part Finder - NGK Spark Plugs

Coli boot kit each x4 Walker products part number 900P2151 or 900-P2151 Bothe same one is an alternative pat number.
Product Categories - Walker Products


You should be able to get both at Rock auto or local parts retailers like Autozone.

 

Much appreciated! I'll probably just go through with Rock Auto or one of the local auto parts stores if they have any promos going on. It's a lot less than $350 lol.

 

Sounds good. Check your pm

 

I said screw it and did the plugs this afternoon during my break. It took me about 1 hour 15 minutes altogether. The metal plate above the plugs (turbo models only) was being a real pain in the you know what, but it was pretty straightforward! The car feels smooth as butter, and seems happier overall. I know that it can just be a little bit of a placebo, but it's noticeble. I'll post of picture of the old plugs later today or tomorrow when I get a chance. Thanks for giving me the motivation to do the job by myself @Callisto ! I only payed $67 for all 4 plugs and like $5 for some spark plug dielectric grease!