When Do You Plan to Replace Spark Plugs?

[TMLifer]

What is the mileage interval everyone is planning to do their spark plugs replacement? There doesn't seem like a lot of discussion on this subject yet since most 6th Gen rigs are probably still new or fairly new. I like what looks to be much easier access to the ignition coils and spark plugs in the 4Runner engine compared to my previous cars which typically required removal of the wipers, wiper cowl, disconnecting wiring, and removing the upper portion of intake manifold in order to access some of the ignition coils and spark plugs.

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[morsk]

I wrote every 40K in my maintenance plan, but I don't remember why lol
I think they may be reasonably changed at much higher intervals, however.

 

[mfoga]

Waiting for the person who does it like 10 times before the mfg recommendation and do the crazy reason why.

 

[TMLifer]

With past cars, I typically did the spark plug replacements at about 90k-100k miles and visually checked my ignition coils to determine whether to replace those. But unsure if I should follow a different interval with a turbo engine.

 

[SteveS]

I plan on 40-50k. Inexpensive maintenance. Saying that, I don’t know if they are special or if Toyota rip you of on the oem plugs?

 

[BruceB]

Toyota maintenance schedule says 40,000. So that is when I plan on having it done.

 

[Gerardo]

I’m following maintenance manual on this one, 40K.

This also maps to recommendations from The Car Care Nut and Simon, both Toyota Master Technicians:

 

[bakutheleo]

I was going to look until I saw it was already answered--I am a little surprised the recommended interval is only 40K miles, but that is what I plan to follow (like the rest of the maintenance).

On my old Sienna I used another brand--I do not recall exactly which, but it was one of the major ones--but went through that manufacturers fitment chart. I was having some minor possible problem--I do not recall if it was emissions, MPG, or what. My smog guy said it is best to use the actual OEM ones. I did replace them with such, and direct from Toyota they were not much more expensive, if at all. BTW, the plugs in that car were a PITA to replace...well, one of them. I think they recommend removing the valve cover or something like that, which is not easy. The second time I decided to try doing it without that and succeeded--one is way in the back and very difficult to get to.

 

[TMLifer]

When it's time to replace them, I'll probably stick with either Denso or NGK iridium spark plugs.

 

[TMLifer]

I was going to look until I saw it was already answered--I am a little surprised the recommended interval is only 40K miles, but that is what I plan to follow (like the rest of the maintenance).

On my old Sienna I used another brand--I do not recall exactly which, but it was one of the major ones--but went through that manufacturers fitment chart. I was having some minor possible problem--I do not recall if it was emissions, MPG, or what. My smog guy said it is best to use the actual OEM ones. I did replace them with such, and direct from Toyota they were not much more expensive, if at all. BTW, the plugs in that car were a PITA to replace...well, one of them. I think they recommend removing the valve cover or something like that, which is not easy. The second time I decided to try doing it without that and succeeded--one is way in the back and very difficult to get to.

Yes, it was a PITA. Depending on the year of Sienna and other Toyota models with the 2GR-FE V6 engine, Toyota tried to optimize the space in the engine bay and tucked a portion of the engine underneath the windshield/wipers cowl, so that the back row of ignition coils and spark plugs were difficult to access without removing a bunch of things. Even then, the removal and installation for the top back side three spark plugs were sort of "blind" without the use of a mirror and light. So it was important to use an universal joint socket to avoid cross-threading when seating the spark plugs with those older Toyota models. They really weren't thinking about how the spark plugs were going to be replaced when they designed the engine bay for some of the older model Toyotas. But I'm happy that the access to the spark plugs is better in the 4Runner.

 

[SteveS]

When it's time to replace them, I'll probably stick with either Denso or NGK iridium spark plugs.

Curious, why not OEM. What is your reasoning?

thanks

 

[TMLifer]

Curious, why not OEM. What is your reasoning?

thanks

Oh I assumed Denso is OEM (original equipment manufacturer) for Toyota and NGK is an OEM equivalent. Is it not?

 

[josiahg52]

Curious, why not OEM. What is your reasoning?

thanks

Dense is probably very likely the OEM? Do you mean why not OE, i.e., Toyota? NGK is another respected Japanese OEM, though.

 

[SteveS]

I seem to remember a thread that summarized that OEM, Toyota, is “different”. Even if the core manufacturer is the same. No idea but if Toyota parts are not too much more in cost, I’ll get them.

 

[josiahg52]

I seem to remember a thread that summarized that OEM, Toyota, is “different”. Even if the core manufacturer is the same. No idea but if Toyota parts are not too much more in cost, I’ll get them.

But Toyota isn't an OEM.

There are really three different concepts people collapse into “OEM”:

Toyota Genuine: Sold under a Toyota part number as a Toyota service part. Toyota controls the specification and sourcing, but it's manufactured by someone for Toyota.

OE/OES supplier: Denso, NGK, Aisin, etc., which manufacture the factory-installed component for Toyota. The part sold under that manufacturer's own brand may or may not be identical to the Toyota-boxed part.

OE-equivalent: A part intended to meet the same application/specification but not necessarily manufactured to Toyota's exact drawing, validation requirements, materials, tolerances, QC process, etc.

And that's the important qualification because you may be correct that “Denso made Toyota's plug” does not automatically prove that every Denso-catalog plug cross-referenced to it is literally the same part as the Toyota service plug. It might be identical except for markings and packaging. It might be manufactured on the same line but to a slightly different specification. Or it could simply be Denso's functionally equivalent replacement.

Toyota can specify things that aren't apparent from the basic catalog specifications—electrode design/material, insulator characteristics, tolerances, validation requirements, QC sampling, and so forth.

Your practical conclusion is perfectly reasonable:

“No idea but if Toyota parts are not too much more in cost, I’ll get them.”

Last time I replaced the plugs in my M5, the originals were $30 or $40 each. NGK Laser Platinums were $18. Choice was easy.

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