Holy crap! Always be sure to fit your boots!

**Updated**

Just got done with a bunch of maintenance work on this newly purchased Tacoma!

Timing Belt, Water Pump, Drive Belts, Valve Cover Gasket, Plugs and Boots.

During the plug change, I noticed one of the plugs was quite a bit bigger than the other, asked asked the PO what the hell that was about.

He said it had been stripped out, and was rethreaded for a bigger size plug.

**Ok, so I was mistaken. The threads were tapped to the normal M14 size using a helicoil repair kit. I thought it was a bigger plug when I pulled them out, because the coil came off with the plug, and having never heard of a helicoil at the time, I didn't suspect anything other than a retap/bigger plug.**

Yay... So I put that plug back in, and put the new boots on.

Truck started well, ran great for a while. On my way home from town, the motor started misfiring extremely badly, pulled to the side and saw exhaust gases coming from that said spark plug hole. I said a few select words and got it home.

Pulling out the boot led to the picture you see below.

Looked into the cylinder to see the plug just chilling there, not threaded at all in place. Pulled it out, part of the old tap set threads came with it. Plug won't thread into place anymore.

Time to rethread, I guess!

My theory is that the boot was not properly seated on the plug, and ended up coming off, letting exhaust escape melting the boot.

Please tell me this is what happened, and it has nothing to do with the timing.

No engine codes appeared, which is strange to me.

 

its definitely caused by that.....good luck with the repair

 

Exactly what I was hoping to hear, thanks! New parts in the mail.

 

this doesn't make any sense, if the threads were stripped on that one cylinder, a helicoil would have been the correct repair and the same size plug would have been used..

sounds to me like a backyard repair gone wrong...you may have a problem getting it repaired, the hole may now be too big for proper re-repair...

 

I was afraid to hear this. I thought the same thing. I suppose I could use a Helicoil and tap a hole for the size of the big plug, I guess. Hopefully I can figure something out, a new head is not exactly on my "things to buy" list.

 

yeah i thought about that too...sounds like a tough repair....i get scared everytime i change the plugs lol

 

you don't want to use a bigger plug...and big bummer, it looks from the pic you provided that this is on the coilpack/passenger side...the rubber boots are made specifically to fit a certain type of plug...it looks like the electrical lead going to the plug head is fubared too...

Did you know about this repair, or was it disclosed when you purchased? If not, I would be hammering the PO for some kind of compensation...he knew how shitty the repair was...

At this point you will probably have to get a shop involved, the head may have to come off even if it can be re-helicoiled, the amount of metal shavings in the cylinder from the repair can present other problems, like scoring of the cylinder walls for one, knackering the piston rings a bit...possible valve or valve seat damage if a piece gets hung when started up again..

You are looking at some expense, no matter what is eventually done to fix...

 

UPDATE:

Ok, so I was mistaken. The threads were tapped to the normal M14 size using a helicoil repair kit. I thought it was a bigger plug when I pulled them out, because the coil came off with the plug, and having never heard of a helicoil at the time, I didn't suspect anything other than a retap/bigger plug.

My mistake.

So now my question is...

Can I rethread a new helicoil there?

There's also the option of Timeserts, but that's much more expensive.

And of course a new head is another option. But again, money.

Heli-Coil - $30
Timesert - $160
New head - $100 (Junkyard) $300 (new)

 

I like the timesert better than the helicoil, but for that price, and still potential problems in the future, a new head might be the best option.

 

Just an observation...yes, you might be able to re helicoil the head, but, definitely going to have to remove the head to do the repair, it is a time consuming job, many things are attached as you already know from the waterpump, timing belt replacement you have already done...

as far as rethreading a new helicoil, the head probably definitely has stripped threads that were made to accommodate the heli...the remaining part of the heli ( if there is any left in the hole)has to be removed (it is now buried deep down the plug hole) and the process started all over again...by the time you pay for machining and whatever, you will probably be ahead of the game with a used (valve seat reconditioned at minimum)head...a qualified mechanic can advise you what is needed...

Bummer, this is going to take some time...hammer the PO for some compensation, this is a repair gone wrong, or done improperly to begin with...

Good luck...

 

A properly installed helicoil should not have come out with the plug unless the po didn't anti sleaze the plug. The boot was most certainly melted by escaping gas, but I doubt it was because it wasn't on the plug the right way. More likely is it that the helicoil was allowing gas to escape. Like most others have said, it sucks to hear, but the best option here is a new/used in good condition head. I wouldn't want to take a chance with it. Good luck man, hope you don't end up paying out the ass for the po's poor decision making.

 

Op take the heads off take it to a machine shop and have the threads done correctly... Have a leak test done first see if you dont have other problems first...

I have heard so many timesert failures do to not doing the head correctly to start with...

Helicoil is Faa cert where the timesert is not last time i checked..


I had a spark blew out on my 5vz.. took both heads straight to machine shop... Read thread all 6 holes for 80 bucks and they are better and stronger than stock... Had the valve guides replaced at 300 bucks when he was in there cleaned up the head some all i can say is she is much torque now than before...

just my .02..