Spark plug replacement surprise

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Make sure you check the new plug gap before installation.

When removing the old plugs, be careful that deposits haven't built up on the end of the plug. It will destroy the threads as you remove the plug. That's why many mfr's say to replace plugs at 50,000 miles or so.

If you think you have deposits, I'd recommend spraying a lubricant (I don't know what is available to dissolve deposits...) thoroughly on the plug, give it plenty of time to soak the deposits, then back-and-forth the plug out. Keep your torque down when twisting the plug out.

Check that all the old plugs have about the same center electrode color. This can range so much that you won't know what's good/bad, unless you've had experience doing carb tuning. Fuel types, engine oil types, altitude and who knows what else can affect the color.
 
The ecu uses the spark plug as a sensor so a lesser qualify or out of spec non oem could affect performance
 
I'd like to jump in and ask if you guys use any anti-seize compound on new plugs? I've read many different opinions about it which fall into 3 categories:
1. Do not use anything
2. Use any anti-seize
3. Use anti-seize for aluminum.

Great thread BTW.
 
I'd like to jump in and ask if you guys use any anti-seize compound on new plugs? I've read many different opinions about it which fall into 3 categories:
1. Do not use anything
2. Use any anti-seize
3. Use anti-seize for aluminum.

Great thread BTW.

NGK Specifically cautions against using ANY anti-seize. You do not gap them either.
 
Mazda Shop manual does not specify the use of anti-seize. I'm not even sure if the original plugs have anti-seize installed from the factory.
 
My understanding is that mfr's use metal types on the thread portion that is anti-seize by nature.
 
I replaced the stock plugs at 75K in my previous '14 Mazda 6. Easy job. I opted to use NGK plugs as I talked to the Mazda parts guy at local Mazda dealer and he stated that the factory plugs are made by NGK and gave me the NGK equivalent to the factory ones. They worked great, ordered from from NGK online and was about 1/4th the price of OEM Mazda plugs.
 
I replaced the stock plugs at 75K in my previous '14 Mazda 6. Easy job. I opted to use NGK plugs as I talked to the Mazda parts guy at local Mazda dealer and he stated that the factory plugs are made by NGK and gave me the NGK equivalent to the factory ones. They worked great, ordered from from NGK online and was about 1/4th the price of OEM Mazda plugs.
Good to know. I'm at 68k. Got a list of things to do, plugs, trans fluid, fresh set of winter tires for next year. I was really planning on trading it in for a new one by now, but have only one more car payment and I don't have any real complaints about it.
 
Care to share the NGK part numbers. :)
Here's a post by mazdadude. The package of Mazda PE5R-18-110 spark plug also showing NGK's part number ILKAR7L11. Although I'm always getting maintenance parts from Mazda, but this one really makes me thinking twice. :)

On this picture of the PE5R-18-110 OEM parts box we can see the NGK # ILKAR7L11
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Here is the ILKAR7L11 plug on amazon...
https://www.amazon.com/dp/ (commissions earned)
 
Care to share the NGK part numbers. :)

I don't remember what the NGK numbers were honestly. I will do the same when my 16.5 CX-5 gets up there in mileage though. Only had it 6 months and already at almost 16k. So they add up fast!
 
I just hope this will be the last vehicle I ever have to worry about changing plugs on(not that it's hard by any means). But I'm going diesel as the next vehicle, so won't have to worry about plugs anymore! I am anxiously awaiting the CX-5 diesel! Finally a diesel in a vehicle that I can afford and like driving! Was hoping to get a F-150 diesel, but they will be waaaaaay out of most people's(including mine) price range. Unfortunate new trucks cost soooo much money!
 
NGK and Denso plugs

Lots of great info in this thread but I wanted to add a bit of data as confirmation of various points already made.

I just spoke with NGK tech support to confirm that plugs I bought from Amazon (direct, not a marketplace vendor) were authentic.
I've started to do this more and more with parts I buy online since cheap fakes are everywhere.

Here's what I learned:

1. NGK is absolutely the OEM for the Mazda CX-5 2.5L plugs you'll buy at the dealer for this vehicle (and most other Mazda plugs).

2. ILKAR7L11/94124 is the correct NGK part number for the 2.5L engine even while it does not have the double tip design like the Denso that some have seen in factory plugs.

3. While not currently an official retailer, NGK is in talks to add Amazon to the official list currently occupied by familiar auto parts retailers so we know the supply chain in place.


About Fakes:

There are lots and lots of fake spark plugs out there that come in nice boxes and look pretty good until you get picky.
If the price seems too good to be true, run.

After talking with NGK about the markings, packaging, etc. we confirmed as best we could over the phone that the plugs I bought from Amazon are authentic.

NGK's main points were that if you paid a reasonable price (I paid $12.89), and the manufacturers lot date code stamped on the hex part of the plug was in their books, the plug was likely okay.
Another item to check was that the washer does not come off and matches the size of the plug.
The ground electrode on the NGKs are very precisely welded and line up perfectly with the center tip.

My plugs are stamped "M714" which stands for the plant (Minamiyama, Japan), the Year (...7), and the week code (14 = April 3). NGK said that that code checks out as an actual manufacturing lot on their books.

NGK stated that the box should also state "Made in Japan" in several languages. Russian characters on the box are a good sign as that is their new labelling standard.
Here's a link to NGK's guide to spotting fakes: http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html


My Experience:

I tried the cheaper Densos and they did not perform as well as the factory plugs or these NGKs. I have no instrumentation to backup that claim, so YMMV.

FWIW, the NGKs all Ohm'd out at slightly above 5k Ohms and were very consistent, while the Densos were more variable and around 4k Ohms. Both numbers are within the spec of 3.07.5 k Ohms.

Here are some pics of the 4 new NGKs and a side by side of the Denso plugs I only ran for around 1500 miles. You'll notice that design of the 2 plugs places the spark at every so slightly a different depth in the cylinder. I can only speculate what kind of difference that might make.


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NGK Plugs.jpg


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Denso and NGK Plugs.jpg
 
Lots of great info in this thread but I wanted to add a bit of data as confirmation of various points already made.

I just spoke with NGK tech support to confirm that plugs I bought from Amazon (direct, not a marketplace vendor) were authentic.
I've started to do this more and more with parts I buy online since cheap fakes are everywhere.

Here's what I learned:

1. NGK is absolutely the OEM for the Mazda CX-5 2.5L plugs you'll buy at the dealer for this vehicle (and most other Mazda plugs).

2. ILKAR7L11/94124 is the correct NGK part number for the 2.5L engine even while it does not have the double tip design like the Denso that some have seen in factory plugs.

3. While not currently an official retailer, NGK is in talks to add Amazon to the official list currently occupied by familiar auto parts retailers so we know the supply chain in place.


About Fakes:

There are lots and lots of fake spark plugs out there that come in nice boxes and look pretty good until you get picky.
If the price seems too good to be true, run.

After talking with NGK about the markings, packaging, etc. we confirmed as best we could over the phone that the plugs I bought from Amazon are authentic.

NGK's main points were that if you paid a reasonable price (I paid $12.89), and the manufacturers lot date code stamped on the hex part of the plug was in their books, the plug was likely okay.
Another item to check was that the washer does not come off and matches the size of the plug.
The ground electrode on the NGKs are very precisely welded and line up perfectly with the center tip.

My plugs are stamped "M714" which stands for the plant (Minamiyama, Japan), the Year (...7), and the week code (14 = April 3). NGK said that that code checks out as an actual manufacturing lot on their books.

NGK stated that the box should also state "Made in Japan" in several languages. Russian characters on the box are a good sign as that is their new labelling standard.
Here's a link to NGK's guide to spotting fakes: http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html


My Experience:

I tried the cheaper Densos and they did not perform as well as the factory plugs or these NGKs. I have no instrumentation to backup that claim, so YMMV.

FWIW, the NGKs all Ohm'd out at slightly above 5k Ohms and were very consistent, while the Densos were more variable and around 4k Ohms. Both numbers are within the spec of 3.0—7.5 k Ohms.

Here are some pics of the 4 new NGKs and a side by side of the Denso plugs I only ran for around 1500 miles. You'll notice that design of the 2 plugs places the spark at every so slightly a different depth in the cylinder. I can only speculate what kind of difference that might make.


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View attachment 217204


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Pretty cool info and insight. Assuming the products are real of course. That said I'm thinking about getting the Denso's over the NGKs. The reason being they could be sourced cheaper (well maybe)plus they have those dual tips. That said both models are within OEM spec and I would be happy with either one.
 
I'm thinking about getting the Denso's over the NGKs. The reason being they could be sourced cheaper (well maybe)plus they have those dual tips. That said both models are within OEM spec and I would be happy with either one.

Thanks, as I stated, been there, done that, and prefer the NGK (OEM) plugs. The price difference on 4 plugs is only around $30 right now.

Try the Densos if you like and let us know what you think as more data points are always good.
 
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