Loose factory spark plugs

Changed my spark plugs this morning and 3 of 6 spark plugs broke loose by hand. One of the ignition coils was brown and smelled like fuel. The cylinder was also brown unlike the rest that were clean. I ordered a new coil. How screwed is my engine because of this. I have 104k miles currently.

 

If there is oil on the plugs, check for leaks on the valve cover. The only time to replace coils if they are really bad, like misfiring or physically damaged. But I don't think discoloration is a big deal. Also, only use DENSO coils.

 

Same thing happened to me. No need to replace the coil. Seems to be quite common actually. Truck ran a bit better after replacement

https://www.tacomaworld.com/threads/spark-plug-psa.766010/

 

Nothing too bad about how it looks.

 

Ordered densos, thanks

 

thanks for the thread. Im glad it isnt just my truck. I ordered a denso coil to make myself feel better

 

What do you mean broke free by hand? Like you were able to turn it with just an extension? (No wrench attached?)

I could rationalize that to myself pretty easily, they have a little crush washer on them, and with all the heat cycles and the fact that you changed them cold, maybe they were just barely snug. Truck still ran, so it couldn't have been too bad.

Not a $30k+ truck, but I had something worse with my chainsaw that I bought used. I was using it for a while, then one day it stopped idling well, and I eventually checked the spark plug and it was both cross-threaded and finger loose. Amazing it ran at all, but in some ways internal combustion engines are quite simple.

 

I actually changed them after driving, but i think thats why there was fuel on the plugs

 

I wouldn’t worry about the spark plugs being too loose, be worried about them being too tight.

 

The boot isn't burnt or melted. Just be sure the metal piece inside the boot is clean from oil or carbon.
Put a little dielectric grease in the lip of the boot (not the plug) and install the new plugs.

The plugs are torqued to 13 ft/lbs
I'm just a public school educated guy from East Tennessee. (dumb ass)
But 13 ft/lbs seems awful low to me. I never torqued a plug in my life.
But I have played around with my (new to me) torque wrench. And I can tell you that I have definitely being getting my plugs tighter than 13 ft/lbs.

My theory is, and it is not a good one, is that maybe the crush washer isn't fully crushed on some plugs at 13 ft/lbs?
If I were to use a torque wrench, I run them down until I fell the washer crush. You can feel plug "bottom out".
THEN, I would use a torque wrench.

Do I use anti-seize? I used to, all the time.
But don't any longer. All the plugs I changed in the last few years were "nickel" colored at the threads.
Which is actually an "anti-seize" feature put on them from the factory. Bosh and NGK both say it isn't needed.

I do still use it occasionally, on the older tapered seat plugs. Like the Autolite plugs with the black taper seat.

 

If it makes you feel better. Do it.
Peace of mind is worth every penny.

Me? - I'm a hack.
And I do most of my own work.
I'd throw that old coil in there and roll with it.
If it caused me issues later, It's my own fault.
And, well, I'd just get to do the job over again.

 

Everything here is pretty much what I do.

And I use a piece of vacuum tube on the spark plug to start the plug in the hole.

 

Nice Toyota. Nice.

 

https://am.denso.com/plug-global/basic/torque/

I never use a torque wrench on plugs, instead I follow the tightening angle (e.g. tighten 1/4 turn after the crush washer contacts).

 

I'd replace that coil. But that's just me

The insulation has been compromised from the extra heat and now more prone to cracking. I don't like spark leaks

How much is a coil, like 40 bucks?

Your engine isn't screwed, it's just irritating to find that

 

$87 for a coil for OEM. Not bad at all. It's just surface staining, but i guess it might have been exposed to higher heat so you might be right about being prone to cracking. Mine was 57k when I replaced them though. I will certainly take a close look at them when I replace the plugs again in a couple years.

 

Same issue with my 2017. I changed them after about 18k miles, but the truck was 6 plus years old at the time. All 3 passenger side plugs were not even finger tight and 2 on the driver side were loose.

Oil changes always smelled of gas until I put fresh plugs in and tightened them down. No issues now and the truck runs so much better. Thanks Toyota.

edit: coils were fine.