Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert!

[MountaineerLC]

Hopefully PK20TT works out but I knew the platinum would not last as long as iridium.

I used the same plugs in mine and have had no issues. As I recall, specs for the 2UZ in the Tundra and Sequoia call for platinum spark plugs. For me, the cost savings made the platinum plugs worth the reduced service life. At the rate I drive, I'm still looking at years of service from the platinum plugs.

 

[abuck99]

Iridium isnt much more expensive than platinum. Engine was designed to run Iridium, why downgrade and impact longevity, performance and efficiency to save $20-$25 over 100,000 miles?

Denso SK20R11 Iridium is what the FSM calls for, they’re under $7 ea on RA and about $7.50 each discounted at the dealership.

Fwiw Platinum draws more energy than Iridium- which puts more load on your coils. If you have new coils maybe not too much an issue early on but with old or original coils, you can accelerate their failure, misfires, and everything else that comes with failed or failing coils.

There’s a list of other benefits you can find online.

 

[BullElk]

Iridium isnt much more expensive than platinum. Engine was designed to run Iridium, why downgrade and impact longevity, performance and efficiency to save $20-$25 over 100,000 miles?

Denso SK20R11 Iridium is what the FSM calls for, they’re under $7 ea on RA and about $7.50 each discounted at the dealership.

Fwiw Platinum draws more energy than Iridium- which puts more load on your coils. If you have new coils maybe not too much an issue early on but with old or original coils, you can accelerate their failure, misfires, and everything else that comes with failed or failing coils.

There’s a list of other benefits you can find online.

^^^^ Exactly right. I have had several coils destroyed and every one of them had the platinum plugs I used in the past. And a few of those plugs were cracked as well. So not a good matching setup. I switched all to the correct iridium plugs and haven't had coil pack issues. Get the SK20R11 every time.

 

[roma042987]

Misfires lead to catalytic converter breakdown so keep that in mind when "saving" money on cheap plugs.

 

[nissanh]

^^^^ Exactly right. I have had several coils destroyed and every one of them had the platinum plugs I used in the past. And a few of those plugs were cracked as well. So not a good matching setup. I switched all to the correct iridium plugs and haven't had coil pack issues. Get the SK20R11 every time.

I've been using Pt plugs on all my vehicles and I have never had an issue. Always buy from a reputed seller.

This is about a spark: Metal that conduct current is the best, so Cu is the best but wear faster so it has a shorter life. Ir is to increase the service life and not to improve the spark.

A spark between two points gives a larger surface area of a flame than a spark originates between two flat surfaces. Since Cu wears out faster, a pointed Cu metal will give may be 10K mile service life hence Ir is better to serve the longevity.

 

[MountaineerLC]

Going platinum may have not been my finest decision, but here I am. I'll report back if there are any issues.

 

[Land Shark]

When I first saw this thread I was like WHAT! I have owned more 4runners, Toyota trucks, toyota cars, Land Cruisers than I can remember. I have changed spark plugs in all of them and some multiple times. I have never, ever, ever, never, ever, ever had any "back out" of get loose/. WTH I said. Oh, and I also used to use never seize on all threads too

It was on the baseline maintenance list of a recently purchased 100 and I ran across this thread so i decided to go ahead and move up this particular item on the list. Low and behold I had one that was not tight. All 7 others were as tight as you would expect them to be. And Guess what that coil boot was cracked and not soft either.

This thread definitely deserves to be a sticky....

 

[CruiserBerg]

When I first saw this thread I was like WHAT! I have owned more 4runners, Toyota trucks, toyota cars, Land Cruisers than I can remember. I have changed spark plugs in all of them and some multiple times. I have never, ever, ever, never, ever, ever had any "back out" of get loose/. WTH I said. Oh, and I also used to use never seize on all threads too

It was on the baseline maintenance list of a recently purchased 100 and I ran across this thread so i decided to go ahead and move up this particular item on the list. Low and behold I had one that was not tight. All 7 others were as tight as you would expect them to be. And Guess what that coil boot was cracked and not soft either.

This thread definitely deserves to be a sticky....

well I guess its worth at least checking all mine tonight. I get super paranoid about engine problems and this will at least put that worry to rest.

 

[Land Shark]

and in all honesty DS was not all that bad to get to. About a pints worth YMMV

And thanks to @2001LC for not letting up on this

 

[abuck99]

When I first saw this thread I was like WHAT! I have owned more 4runners, Toyota trucks, toyota cars, Land Cruisers than I can remember. I have changed spark plugs in all of them and some multiple times. I have never, ever, ever, never, ever, ever had any "back out" of get loose/. WTH I said. Oh, and I also used to use never seize on all threads too

It was on the baseline maintenance list of a recently purchased 100 and I ran across this thread so i decided to go ahead and move up this particular item on the list. Low and behold I had one that was not tight. All 7 others were as tight as you would expect them to be. And Guess what that coil boot was cracked and not soft either.

This thread definitely deserves to be a sticky....

What plug #No. was loose??

 

[Land Shark]

Man I should know the actual number but having a brain fart right now... HA. It was DS 2nd from the fire wall.

 

[Land Shark]

And when I say loose I mean only like a thread or two loose

 

[Land Shark]

Picture of plug

 

[nissanh]

I installed these Pt plugs at 222 K miles in 2016 and retorqued in 2020. At 247 K miles , I threw in a new Pt set again. Old ones were not super tight or super loose. Newones went in with a dab of antiseize at 20 ftlb. Needs two new coils (got a minor crack) and will get those done in Summer.

Orientation: Bottom row is driver side: Far right is near firewall

 

[Wildcat Walker]

FWIW NGK and Denso do not recommend applying anti-seize to spark plug threads. This is due to the insulating properties of the paste. I do usually add a very small amount, but I also change plugs at normal intervals.

 

[Land Shark]

I am going to post this here since I think its relevant and if not can move... A couple of weeks ago I jumped in the 100 (started right up strong) drove 25mins across town and shut off engine for about 15 mins. Upon starting again the engine only turned over (very strong, not weak). HMMM. immobilizer? fuel pump? ????? I went the easy route first and checked the fuse for the EFI and it was good. Although it was a 15amp not a 20amp. (interesting). So I waited and about 10-15 mins later truck started right up strong just like before. So, I went ahead and just ordered a fuel pump seeing that it was not a ton of $$$ and an easy DIY. Fast forward a week and I am changing out the plugs, as posted above. Could the loose plug/cracked coil boot have been the issue. Truck would have still been very hot at that point hmmm? Any input here is appreciated.

 

[nissanh]

I am going to post this here since I think its relevant and if not can move... A couple of weeks ago I jumped in the 100 (started right up strong) drove 25mins across town and shut off engine for about 15 mins. Upon starting again the engine only turned over (very strong, not weak). HMMM. immobilizer? fuel pump? ????? I went the easy route first and checked the fuse for the EFI and it was good. Although it was a 15amp not a 20amp. (interesting). So I waited and about 10-15 mins later truck started right up strong just like before. So, I went ahead and just ordered a fuel pump seeing that it was not a ton of $$$ and an easy DIY. Fast forward a week and I am changing out the plugs, as posted above. Could the loose plug/cracked coil boot have been the issue. Truck would have still been very hot at that point hmmm? Any input here is appreciated.

When engine is hot, coolant is hot, which sends a signal to ECU to be in closed loop which then adds small quantities of fuel (short pules width) at startup. clogged injectors can cause the symptoms you stated. Try running fuel injector cleaners (I find gumout giving good results). Next are the coils OEM? Heat can cause the resistance to increase.

 

[2001LC]

Denso, Toyota, etc. recommend: When threads lubed (i.e. anti-seize, oil, grease, etc). Reduce torque by ~25%.

If anti-seize used on a spark plug. If threads then get hot gasses (loose spark plug) blow-by. The anti-seize will cook into threads, making removing plugs, very difficult.

 

[Land Shark]

Thanks fellas for the input here. To my knowledge these were all original to the vehicle with 174k on the clock. I replaced all plugs with OEM. Will be replacing the coil with the cracked boot etc in the next couple of days. Will run some FI cleaner through it as well.

Per advice in this thread I did no use anti-seize.

I also noticed that when I removed the plugs they were a small bit gritty. When I threaded the new in it had a pretty smooth feeling.

 

[T4R2TLC]

I just replaced my plugs due to not knowing their history and a bit of paranoia from this thread.

Sure enough they had baked on anti seize that made them a chore to remove and at least a few were backed out enough to toast the boots as well.

The burnt boots crumbled to bits, so I was glad I had the new Denso set on hand.

Upon re-assembly, what I thought had been a header tick when cold was gone—the tick was from a loose spark plug (or multiple). Huge relief and beyond glad that I did this now rather than waiting for catastrophe.

What is interesting and scary is that (IMO due to the anti seize) the plugs can be very tight in their threads and yet also have backed out far enough to leak when cold. In my case this made the job a little harder than it should have been yet very very worthwhile.

If you haven't replaced your plugs yet, please do. A very very easy job even if they are seized in the heads, just take your time and work them out slowly, luckily the access is very easy.

Notes:
Parts used were Denso (4702) IK20TT (x8), Denso 671-8184 (x1)
Torqued plugs to 17ft-lbs
Used pb-blaster on plug removal, not ideal but better than a broken plug