Spark plug hole stripped/coil melted

[MADMARTICUS]

This is the second time my 96, toyota 4runner3.4l, blew out the sparkplug, threads and all. Not only that put this time it blew out the Heli coil I installed last time and melted the second coil.

Does anybody know why this happens or seen this before.

I posted some good pics.
Please help if you can.

 

[drmorbius]

This is the second time my 96, toyota 4runner3.4l, blew out the sparkplug, threads and all. Not only that put this time it blew out the Heli coil I installed last time and melted the second coil.

Does anybody know why this happens or seen this before.

I posted some good pics.
Please help if you can.

I'm guessing that someone cross threaded the plug hole before you got the vehicle which led to the first failure. Did you pull the head to do the Helicoil install? If it was mine I would get another head and do it right. I know it's a big job and not cheap but the band aid approach doesn't seem to be working. It's a high stress point and it would be hard to keep the Helicoil sealed and locked in place. The melted coil points to hot gas leakage past the threads.

 

[Stick Figure]

Helicoils are good, but time serts are better .... try the time sert http://www.timesert.com/html/sparkplug.html

if that doesn't work, you could always pull the head and have it welded and re-threaded, but the time sert should be more than good enough to fix the problem.

 

[MADMARTICUS]

Thanks but that's not an easy task for me. I live in Germany and it would be hard to find a new head without paying to much.
I just don't understand why it blew out the hole twice. The coil did not melt til after the spark plug blew and my wife drove it home.

How do I know it's not something with the wiring going to the coil maybe getting the plug to hot?

I put in the helicoil last time, ayear ago and yes it happened the first time because a mechanic in CA crossthreaded it while I was in the desert.

I just don't understand the problem. If it wasn't for that the truck has ran great w/ no major maitenance.

 

[MADMARTICUS]

To Sticky

Well I guess it wasn't a Helicoil that I installed, it was a Timesert.

I also did a compression ck and everything seemed good after installing the timecert with lock tight.

 

[drmorbius]

To Sticky

Well I guess it wasn't a Helicoil that I installed, it was a Timesert.

I also did a compression ck and everything seemed good after installing the timecert with lock tight.

I can see where a compression check could look normal, but once you start the engine you literally have explosions going on right under the spark plug. Also if the head is aluminum and the insert is steel then they are going to expand and contract at different rates during heating and cooling which could eventually crack the sealer allowing leakage.

 

[MADMARTICUS]

Thanks for the help, now I just need to find a head.

 

[drmorbius]

Thanks for the help, now I just need to find a head.

I just did a quick search because I feel your pain. You might try this link and see what develops.http://www.toyota-4runner.org/showthread.php?s=&threadid=41592 Good luck!

 

[Stick Figure]

Yeah if the Time sert is failing, you are pulling the head for sure. I don't know whats really available to you in Germany, but it might be worth making a few calls to see if there is a machine shop that could actually repair the cylinder head. Otherwise car-parts.com shows them from $400-around $100 for a single head. Shipping is gonna cost though. I would check yota techs classifieds as well for some heads.

 

[Victor]

Unfortunately, I have seen this case before. I repaired one where the #6 Spark plug had blown out and had destroyed the threads and had melted the coil pack on the way out. Your only option is to remove the head and have it repaired by a good machine shop. You can try to helicoil or the timesert, but lots of filings will fall into the cylinder and may or will score up the cylinder once it comes in contact with the piston.

 

[clt750]

I just had this exact same thing happen on our 2000 4 Runner twice. The first time I just replaced the plug and bought a new coil pack. That was 1 week ago. Today it did it again but the this time I cant thread a new plug in. The threads on the plug are mangled which tells me the head threads must be mangled too. The plug is in really bad shape. #1 cylinder.

What I want to know is why? I have no Helicoil or Timesert. All stock. The plugs have been in there a while (1 1/2 to 2 years) but I dont think that should cause this issue. I do have an exhaust leak on that side but I dont think its that bad of a leak.

Not a happy camper. Not how I wanted 2011 to start either. :wtf:

 

[broncosi]

Same thing happened to me last night. For the second time as well. I'm having it towed to a machine shop in the morning to have them fix it up. Talk about a day ruiner, I had tickets for a dubstep show in another city that I was supposed to meet people there and I bought a shirt for the show that was a $40 cool equalizer tshirt and had it overnighted from ca for the concert.

 

[hairysrunner]

Sorry about your troubles,
I had the same thing but on a Ford expedition a few years ago. I was sure that the engine was internally damaged so I sold the truck for what I could get out of it. With the miles on it and the other upcoming repairs I simply did not want to put more money into that pit(Ford 5.4Litre v8) consider all your options before you pull the head and start drilling. Inserts don't always work or last. Good luck and I hope it all works out for you.

 

[matthinnant]

Well if you do end up buying a new one online or something you could always have a buddy stateside perferably military ship it to you APO to APO is free for military and im guessing your still in being at ramstein and last year you were in the desert. Just a quick ? are you in the AF if so whats your AFSC. im in the AF gotta a few friends over in Ramstein just curious if your same careerfield as them or me