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Spark Plugs - so many choices!

For many years I drove company cars, when they needed maintenance they went to the garage. Now I’m retired and I need to save some money, and I used to enjoy working on cars, way back when.

Now I want to change out the plugs on my Toyota Sequoia, '01, 4.7L V8. They look easy to get to and I think I can do this. I went to the Auto Zone web site and there are 3 pages of plugs that fit. Iridium, platinum, cooper, and a few basic. Prices range from $8.00 ea. to $1.79 ea. The owners manual says replace with non-platinum plugs every 30K miles. I haven’t pulled a plug yet so I’m assuming the plugs in there now are not platinum. Regardless I don’t know when the last plug change was done since I bought the car recently.

I’m be putting less than 5,000 a year on this car. If I put in a platinum plug it may rust in place before I ever need to change it. I figured to get a more basic plug and stick to the 30K change as per the Toyota schedule. There is a Bosch Copper for $1.99. Does this make sense or not?

Are the fancy plugs worth the price given my usage? What brand, type do you recommend?

When I change them should I put oil or something on the threads? Do you guys routinely use the electrolyte grease when installing the boots?

Anyone remember “fire injectors” from the mid 60’s? I paid a bunch of money for a set and put them in my '67 Mustang (289) and they were a bust. So, I’m a bit leary of big money fancy plugs.

I’d replace them with exact OE replacements. Nothing fancy.

Bosch copper, or NGK copper would work fine, as would many other brands. Many Toyota folks like NGKs. Get a tube of antiseize and put it on the threads of each new plug as you install.

Here’s another vote for NGK, the brand I prefer in Toyota and Honda engines.

My choice would be the original equipment as recommended in the owner’s manual. Back in the 1950’s, I think every engine we had from the 2 cycle lawnmower, the 4 cycle tiller, the 1952 Dodge 6 and the 1954 Buick V-8 would all run on Champion J-8 spark plugs. We would just buy a couple dozen plugs and tune up everything. Those days are gone. I use what is specified by the manufacturer for the cars I have now.

Once in the earlier time period I tried spark plugs with multiple electrodes in the Buick. These were supposed to give added power and save gas. They fouled out very rapidly. I cleaned them up and tried them in the lawnmower. These plugs didn’t even work well in the lawnmower. Skip the fancy plugs.

I prefer the OE plugs. Although other plugs should work, occasionally people post here with issues caused by switching to other brands of plugs.

That is NGK BKR6EYA or DENSO K20R-U from my owner’s manual.

OE is your best bet.

While I have never used them, I have heard horror stories about the Bosch platinum plugs that you don’t gap. There are four sitting in my garage that my brother wanted put into his Grand AM. I told him if he wanted plugs that were that different looking, he better get someone other than me to put them in. He bought regular styled platinum plugs and I used those instead. I don’t like going back and doing work over because of bad parts.

I also don’t think going up in metals (ie; copper to platinum) is a problem, but I would still at least pull them out and check them at the required maintenance schedule, to see how they look. My vehicles they are all out of any type of warranty, so I tend to check everything much more frequently than required, if it looks bad I replace it, if it looks OK I will leave it in for a few thousand more miles.

Absolutely use the NGK OEM replacements listed. They are one of the two (the other being Nippon-Denso) that Toyota has approved as original equipment.

The question should not be “are the fancy plugs worth the price”, the question should be “are the CORRECT plugs worth the price”. The answer is YES!

“Fire injectors” are “fancy” plugs…but not the CORRECT plugs. “Fancy” plugs are never worth the price.

the owners manual says replace with non-platinum plugs every 30K miles.


Anyone remember “fire injectors” from the mid 60’s? I paid a bunch of money for a set and put them in my '67 Mustang (289) and they were a bust. So, I’m a bit leary of big money fancy plugs.

They went bust because they were JUNK. NEVER did what they claimed…NEVER will.

The ONLY thing the platinum plugs or Iridium plugs will do for you is last a lot longer. And personally I don’t want to leave plugs in there that long.

The cheaper copper core plug will work just as well as the Platinum and Iridium plugs. You will not gain one iota of horsepower or fuel economy by using the higher priced plugs.

The only advantage the Plat. and Iri. plugs have is they have a bit more longevity and are less prone to subtle misfires after a certain mileage.
Plain copper cores in a non-oil burning or poorly running engine should easily go 30-40k miles and more.

My personal preference for plugs is Bosch, NGK, and Autolites. Never had problems with any of those brands.

Yes on the grease for the boots,I think the word is electrolytic (someone correct me here) Thats it dielectric just could not place the word.

Get the plugs from the same manufacturer as came in the new vehicle. There are subtle differences in plugs from other manufacturers. Do what the manual says as far as antiseize. The torque figures are different for lubricated and dry threads. The OEM plugs are probably nickel plated. That IS antiseize. You MUST have a torque wrench if you have aluminum heads and plugs without the crush washers. Be sure to blow the crap out of the plug wells before you take out the plugs.

The recommended service for (the single plat) plugs in my daily drive with aluminum heads is 100,000 miles. I took them out early at about 95K with no problem and they looked pretty good. I had no trouble getting them out.

The difference in the price between copper and single plat plugs is going to be about 8 bucks for your V8. I would not consider the copper plugs at that difference if the OEM is plat. If they are copper, I guess I would consider it just to keep it as the engineers designed it.

Yes, use a little dab of dielectric grease on the boots. It will make it easier to get them off and keep moisture out. The price of those tiny tubes at some auto parts stores is ridiculous. I like to use it on many automobile electrical connectors and in outdoor light bulb sockets. Here is a good post discussing alternative sources:

Yep, just original equipment NGK-don’t get fancy.

Absolutely necessary to use anti-sieze compound on the threads and using dielectic grease on the boots helps to get them off again. Best thing you can do is buy a factory repair manual to get your feet wet.

Dielectric - that’s the word…I always have the same problem with ‘invented’ words.

I just use the OEM spec plugs, gap them correctly - for V8’s I pour a glass of good red wine since I find it helps with my feeler gauge sensitivity (I find the same effect with micrometers) - but just one glass eh!

I check/regap plugs every 3000 mile oil change and replace at every third oil change regardless of plug state. Unless otherwise specified I use standard Champion plugs, gapped to spec and thread greased with copper grease. The grease also picks up the grit when you’re pulling the plugs (though I also use kerosene and an air line).

Never failed me so far

Toyota. If you replace plugs, you should use NGK or ND. A sticker somewhere under or on the hood may have the exact one listed. Maybe in the owner’s manual too. Never use any other plug, not Bosch, AC, Champion, Motorcraft. Never, unless the car recommends it. Keep in mind that I only think NGK or ND is the recommended brand. You should check. If you have never changed a plug, this is no time to start; you have eight chances to get it wrong. Exotic plugs are still worthless.

Wow! So much to consider. Wet and dry torque, blow the junk out, oh my. It has been awhile, and surely I don’t want to strip out the treads on an aluminum head. I have a torque wrench, I got the message and will use OEM plugs, and I’ll need to find a way to blow out the plug holes before pulling them. I don’t have compressed air, so I may have to try my electric leaf blower.

Appreciate all the advice. Tomorrow I’m getting the timing belt changed on this car. If the price of new plugs isn’t too bad I may leave it up to the pro.

I would advise that if you do the plugs yourself that you not even use a torque wrench.
The reason for this is that most torque readings are (comparatively) low and readings in the 15 ft. lbs. range is entirely too much for an aluminum headed engine. This is especially true for plugs with shallow thread depths.

JMHO, but I never use a torque wrench on spark plugs. I use a stubby 3/8 drive ratchet and palm it. The simple act of palming it will provide all the torque you really need and will prevent any problems from cropping up now or later; with the later meaning “pulled” threads. Pulled threads can be a problem later on.

I don’t have a problem with using a torque wrench if it’s a small drive (1/4 or 3/8 at most) and if it’s KNOWN to be accurate. Even then I consider specifications such as 15 ft. lbs way too high and 7-8 ft. lbs. is more like it.
(Would also point out that I’ve seen specs given for a specific application and one chart will say 16 ft. lbs. and another chart will show 8 ft. lbs. Err on the side of caution and take the lower figure.)

In my experience OEM plugs and wires work best. Fancy plugs and wires tend to work as good or not as good, but not better.

No need to get exotic here. If you don’t have an air compressor, simply get a 2-3 foot length of 1/4 inch plastic tubing and blow into one end while the other end is in the sparkplug well. A couple of puffs should do it.