Spark plug ejected on my 3.5L, stripped head

So, my 2017 TRD Sport purchased certified preowned at 7k mi has required nothing but oil changes and brakes up until now, always dealer serviced. At 118k my engine apparently spit out a plug and stripped the threads on the head. Heard a progressively worse ticking noise for a second, rough idle, by the time i pulled over and then tried to move the truck to a better spot it lost power and that was it. Towed to dealer who diagnosed the issue.

Head is roughly 8500 all included, used engine coming to around 9500 depending on what they find. Reached out to Toyota corporate for possible assistance, call back a day later saying case closed you're on your own.

I declined plug service until next visit recently and they might be using that against me here. Can't imagine this is normal for being slightly over for plugs, though?

So really I'm just putting this out there for the record and also wondering if anyone had any info or advice that might be helpful. Ive searched and seen a lot of reports of loose plugs from the factory but very few stripped heads as a result. I was also sent a screenshot of a Toyota tech facebook group reporting plugs coming loose on a lot of Tacomas around 130k recently.

Has anyone had any luck with a product like Time-sert inserts on the 3.5L? Can it be done without pulling the head? Toyota tech said he was skeptical it would hold due to "that area getting very hot and cold frequently."

Any thoughts from you all are appreciated. Not a great time for such a huge expense on my end and not sure about spending so much on a vehicle with 118k already despite many going to 300k+.

Peace

 

I’m curious, are these the original plugs or were they done at 60K?

 

I do ALOT of sparkplug thread repairs using "time-sert" brand inserts, specifically designed for sparkplug thread repair.
Cylinder head does not need to be removed to do this type of repair & will last the life of the engine if done right.
I DONT recommend the cheaper kits that you can get at the local auto part store....

Do you have any engine rebuilders / machine shops in your area, make some calls, they may do it for you & have the kit....
The time set tool kit isnt the cheapest but far superior than the rest of the inexpensive kits...

You only have 1 shot, do it right.....

 

Time sert it...be good as new

 

If toyota doesnt assist, ide do / try an insert from a reputable shop before I tossed a head at it....
I charged 4.0 hours labor on any ford, + a new sparkplug & coil.....
You also want to check your remaining plugs checked for tightness, or replace....

 

Thanks for the feedback on the inserts and reminder to check the rest of the plugs. I'm definitely going to look into the insert more, any recommendations for shops in New England? And has anyone done or heard of it being done on a 3.5L specifically? Lots of reports on the 4L but having trouble finding them on my engine. Are the plugs a lot more recessed on the 3.5L compared to other engines making the job more difficult?

@BLtheP I was never recommended plugs before about 110k (from what I can remember) and I assume they weren't done before I got the vehicle, so original plugs.

 

https://www.timesert.com/html/sparkplug.html

Maybe search yelp in your area?
machine shop, engine rebuilder, etc...
Some mechanic shops will use a cheap kit from Amazon or auto part store & theyre like $25....
They just dont hold-up long term & next time someone pulls that sparkplug, theres a high probability that the insert will come out with the sparkplug vs staying in like it should....

 

There are specific maintenance requirements for spark plug replacement, oils, etc. You have done none of that?!?
That plug has been loose for many thousands of miles for sure. If all the OEM plugs had been replaced at 60k miles, the new plugs should have been torqued to 13’/lb spec.

 

I should have mentioned I've called 3 shops about the insert so far and none have inspired confidence.. one outright said bad idea do what toyota says. Still looking but any recommendations are welcome.

 

pretty sure this is the kit that you need...
but dont take my word for it, you can actually call timesert....

Its just nice to find a shop that already has the toolage.....

The inserts are cheap...


https://time-serts.com/store/m14x125-spark-plug-extended-kit-washer-seat-pn-4412e-111/

 

@eurowner I've done all recommended maintenance and oil changes every 5k at the dealer

 

I used a cheaper version on a 1st gen Highlander before selling it ten years ago. I still see the car around occasionally, and just saw it last week. That said, I would definitely use Time-sert if I were to do it over. I wasn’t aware of Time-sert at the time I repaired the Highlander.

 

Thats cuz everyone you called so far sucks & are clueless....

Ive been a ford engine tech for 32 years & the 5.4L, 6.8L / v10 with aluminum heads have been ejecting spark plugs forever....
Ive literally have inserted probably 500 sparkplug holes & probably twice as many engine oil pan drain plug holes....
Even ford has their own branded kit now, along with ford ESP warranty authorizes inserts vs replacing the head....

Not a bad idea at all & will save you $8k if you find someone who has a clue....

Start digging deeper into engine rebuilders, machine shops....
They all use them, its common practice in the machining world....

 

It's crazy the dealer didn't recommend a plug change long ago.

 

Can you be more specific with the area you're in? There's a pretty active NE BS thread you can ask for shop recommendations there
https://www.tacomaworld.com/threads/new-england-b-s-thread.204874/

You could also ask in this thread. Lots of guys doing their own work and might have a good connection for you
https://www.tacomaworld.com/threads/new-england-mod-meetup-renaissance-group.762539/

 

Gotcha. The reason I ask, is because while technically the plugs can go longer than the 60K service interval, I was wondering if they had been touched before. There have been a lot of 2016-2017 Tacomas (and some other years sometimes) where the spark plugs were found very loose (from factory) when people went to change them. So I wonder if yours was loose for a while, and since they were never touched, it went a long time not dealt with and eventually the compression forced the plug out and ruined the threads.

 

At my dealer we have a master kit of all standard & metric insert sizes & required tools....
We dont use garbage held-coils for anything!
My service manager started as a engine line tech like myself & he bought / brought the kits in after he became service manager as he knew the importance of them.
For the last 15 years I was the one who serviced the kits, made sure toolage weren't damaged, replaced as needed, ordered various length / size inserts, etc...

Its not a hole in the wall off brand that nobody uses, you just need to find the "real shops" that aren't hacks & take bride in their work, want the best...
Machine shops, dont mess around...
Well I can with confidence say atleast the ones in San Diego....

I have no idea what they do in isolated small towns do....

 

I've seen quite a few 3rd gen v6 3.5 Tacomas with loose spark plugs from the factory. Enough that I would recommend doing them early. Or at least checking torque on them before the scheduled maintenance.

 

thats what happens...
They get loose & every time they get hammered from the sparkplug firing & compression, they rotate counter clockwise & damage the threads badly....
Very doubtful that just cleaning up the threads with a tap will work....
Has only worked on one ford for me, usually the threads / metal is gone...

Look at the coil boot, burnt to fuck, that didnt happen overnight.
Its been making a very slight tick noise for a long time but the coil muffles the noise...

 

Might get lucky & it may accept a new sparkplug without any tapping or anything, ive had that happen once also.....
We dont have a picture of the threads in the head.....

Thing is since its not a common accorance with toyota, they may be clueless about the time-sert option.

Or, go down there & talk to the shop foreman, maybe he's familar & theres a tech at toyota that does them all the time.....

Just not the tech that was assigned to your vehicle.

I was terrified first time I installed one in a head....