Spark plug change in Rav 4

Just changed my plugs on my 2015 Rav 4 (108700 miles). I had changed the originals with Denso Iridium plugs at about 40k and then at 76K. Now I upgraded to NGK plugs (Iridium). I searched for the correct amount of anti seize (I tend to over do things) and found a lot of articles that for the expensive NGK plugs, you don’t and shouldn’t use anti seize so you don’t over tighten the plugs (that is the reason for the post to educate some like me who didn’t know about this rule). Even with anti seize, the 2 left plugs came out very slow and difficult to turn the ratchet (6") with extension bar. The 2 right ones came out very easily after breaking them loose. When I put the new NGK’s in my hand, they spun down extremely easily. I tightened like I always do and used boot grease. When I started the car, it was quiet and smooth. I’ll drive it later today but even though the old plugs had 33K on them, they were white and looked fairly clean (yeah, they can go 100K but I like to change them due to being able to get them out of the head). Now on to my wife’s Kia Optima with 45K (orig plugs of course). I got NGK for hers too but her car (optimas between 2014 and 2016 burn oil… at least 1 qt per oil change) so I’ll see how they look.

I would strongly recommend that you stick with whatever plugs are listed in the owner’s manual. OEM is your friend here. Modern engines tend to do weird stuff when you try to “upgrade” your spark plugs with “hotter” ones.

Perhaps that’s what you’ve already done, and if so, feel free to ignore this post.

1 Like

I agree with that.

I also understand the argument against not using anti-seize. But I always use a small amount. And, while I’m a stickler for following torque specs on things like brakes, engine, suspension parts and the like, I’ve always done plugs by feel.

I’d be happy to hear what the career mechanics do.

1 Like

I don’t know why people go crazy and replace expensive iridium plugs before the interval. I have left iridium plugs in for 100,000 miles and, if they are NGK or Denso, they always turn right out without any difficulty. Even after 100,000 miles they typically look great, so what’s the rush to spend 10 to 20 bucks a plug any sooner than I have to?

My one kid had a car that he got from my ex-wife’s boyfriend. A Dodge Avenger with 137,000 miles with original plugs in it that were 10 years old. Even those ones came right out without any difficulty.

My understanding is that modern iridium plugs have a zinc or some other coating on the threads that keeps them from seizing in the head of the engine. I have yet to encounter a modern plug that didn’t come out easily, regardless of time and mileage.

Did you put anti seize on the plugs the last time you changed them?
Maybe that is why they were too tight.


I had my own place for about 8 years. We used OEM plugs. I had a guy working for me that insisted on using anti-seize on spark plugs even after I stated not to. Eventually I had to throw away all the anti-seize in the shop to make my point.


Us old farts used anti-seize back in the day when cylinder heads were cast iron, and spark plug threads were copper coated.

But new spark plugs have platinum or iridium coatings, and they’re going into cast aluminum heads. So anti-seize really isn’t required anymore.

But more important, using anti-seize can give false torque reading, or feel when tightening the spark plugs.

On a cast iron head, it was pretty hard to rip the threads out from over torquing. On an cast aluminum head, it can happen in a heartbeat.



It’s not just isn’t required - it changes torque spec if used on plugs that are already coated. NGK even has a warning NOT to use it.

1 Like

Ok - I’m done with with the anti seize on plugs. Thanks @asemaster & @Tester.

too late. they were on Rock Auto Parts so… It runs fine so far. I’ve used Denso ones the other 2 changes. they were okay too. NGK are supposed to be one of the best kind of plugs. they did screw in by hand really nice I’ve got to admit. I’ll find out in 3 years how they come out.

I think the Denso plugs are listed as OEM equivalents. I have used anti seize for almost 50 years but NGK has a lot of info saying they plate their plugs so they go in and out very easily. I had AS on the denso plugs and those 2 on the left were really tight to get out. Granted, I was using a 6" socket so I didn’t have a lot of torque but the 2 on the right spun right out after I broke them. The treads on the left 2 were fine. Not sure why they were tight. And I tend to put a lot of AS when installing so… I’ll see how my wife’s kia plugs come out soon. I got NGK there too.

they came out but 2 were snug and I needed a lot of muscle to get them out. I did tighten the new ones till they hit and then 1/2 turn where they couldn’t go anymore without excessive pressure. Never had an issue that way. One day I’ll learn how to calibrate and use my 19" torque bar.

yes. and I usually put a good bit and swirl around the plug to spread it. If anyone knows my posts, I baby and change things way ahead of time. Gives me something to do. Autozone cost was 12 and 13 for the 2 kinds of plugs (rav and kia). I got the NGK’s at Rock Auto for $6 each so it wasn’t bad.

Not that it is a big deal but your posts are seen by everyone so no need to reply to each person .

Also it seems that you are changing plugs more than necessary.

that was my reason for the post. Trying to educate as I didn’t know it. Did a search on how much and NGK said don’t use it. They went in really easy relative to the Denso plugs when I installed those. But I’ll see in 3 years how they come out. What’s the worst?? a new head and new plugs (NLOL). Thanks for the comments.

sorry, 6" is the 1/4". The 9" is 3/8 but you all know that.

Denso and NGK are OEM plugs for Toyota. My 4runner came from the factory with NGK on the drivers side bank and Denso on the Passengers side bank. Denso also coats their plugs now and recommends against using anti-seize.