Is cylinder #4 trying to tell me something?

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Changed out my plugs today on my Mazda 3. 4th cylinder is a bit cruddier than the rest with some carbon deposit on it. Not really oily. The electrodes seem fine but clearly from the pic there is something going on with the one. Is this normal? should I be using a fuel additive a time or two?

[Linked Image]
 
Originally Posted by OVERKILL
Is that the cylinder closest to where the breather or PCV meets the intake? If so, that's normal.


Yes, it's furthest right plug closest to the intake.
 
Originally Posted by jayjr1105
Originally Posted by OVERKILL
Is that the cylinder closest to where the breather or PCV meets the intake? If so, that's normal.


Yes, it's furthest right plug closest to the intake.


Yeah, so it's getting the crankcase fumes/oil mist. So perfectly normal.
 
I would suggest installing a catch can to prevent much of the vapors from going into the intake.

If #4 is where the return water from the radiator enters, it may be running a little cold. You can use carboard to block half of the radiator in this kind of weather, Just do not forget it come spring.

Rod
 
Originally Posted by OVERKILL
Originally Posted by jayjr1105
Originally Posted by OVERKILL
Is that the cylinder closest to where the breather or PCV meets the intake? If so, that's normal.


Yes, it's furthest right plug closest to the intake.


Yeah, so it's getting the crankcase fumes/oil mist. So perfectly normal.

Thanks for the confirmation. Is an oil catch can really necessary for this motor?
 
Originally Posted by jayjr1105
Originally Posted by OVERKILL
Originally Posted by jayjr1105
Originally Posted by OVERKILL
Is that the cylinder closest to where the breather or PCV meets the intake? If so, that's normal.


Yes, it's furthest right plug closest to the intake.


Yeah, so it's getting the crankcase fumes/oil mist. So perfectly normal.

Thanks for the confirmation. Is an oil catch can really necessary for this motor?


No, and a catch can won't eliminate all of it anyways and just gives you something else you need to worry about.
 
The tip and porcelain look clean, so a hotter plug is not needed. The build up is on the threads. The only problem i would see, is if you are not careful removing the plug with a lot of build up. If you meet resistance removing that plug, work it back and forth slowly, till its worked out.
 
Originally Posted by spasm3
The tip and porcelain look clean, so a hotter plug is not needed. The build up is on the threads. The only problem i would see, is if you are not careful removing the plug with a lot of build up. If you meet resistance removing that plug, work it back and forth slowly, till its worked out.


That plug did give me a little more resistance than the others but nothing crazy. They all came out just fine with a regular 3/8 ratchet. I went with Ruthenium because they were $7 a plug from RockAuto and the NGK laser iridiums were over $10. We'll see how they pan out but car is running great.
 
...just be aware there is a slew of counterfeit iridium NGK, and others, sparking plugs out there. Just a thought...that's my go to plug, but have to be careful where I buy them anymore. I've been burnt more than once with fraud plugs on eBay...center electrode burnt off to the porcelain before 6k miles.
 
Originally Posted by ddtmoto
...just be aware there is a slew of counterfeit iridium NGK, and others, sparking plugs out there. Just a thought...that's my go to plug, but have to be careful where I buy them anymore. I've been burnt more than once with fraud plugs on eBay...center electrode burnt off to the porcelain before 6k miles.


Yep. There's ways to tell the fakes from the real ones. The NGK letting will be slightly off center, and there's some differences in the part number on the mid section. I ordered a set off Amazon that ended up being fake. Amazon took them back and gave a refund. I only get them from NAPA now.

Brake pads are getting that way now too. A friend of mine bought a set of Hawk brake pads for his car and chunks of the pad broke off within just a few hundred miles. He called Hawk and they described exactly what the fake looked like and it was what he had.
 
I stopped buying certain things from Amazon and instead from RockAuto. Spark plugs, water pumps, etc. Anything that can grenade your car or something that takes serious labor to install.
 
Although the assumption has been made that it's crankcase gasses carrying a bit of oil and making it's way to plug 4, it bears mentioning that it may not be blowby causing this. I'm not at all sure the PCV system loads this cylinder more than the others. Can you provide a pic of the engine and PCV system?
 
Originally Posted by jayjr1105
I stopped buying certain things from Amazon and instead from RockAuto. Spark plugs, water pumps, etc. Anything that can grenade your car or something that takes serious labor to install.


I have lost my confidence in Amazon. I will only buy if its being sold by Amazon itself. Lots of counterfeit, misrepresented stuff or unauthorized substitution, in my opinion. I only buy from RA because I get what I ordered.
 
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