No it's not normal, but over-torquing spark plugs is usually the issue. It strips the threads and then the compression just blows the plug out. We have aluminum heads so the metal is soft.

thank you for that link, but that still didnt really answer my question. it just looks like a burlier helicoil that takes extra steps to install.

im not for one or against the other. i just have a hard time trying to figure out why this type of thread repair is more desireable for spark plug threads. is it cause it holds onto the soft aluminum better?
christ, rookie hour. do people not own tq wrenches?!

Yes. You probably dont need the high temp JB weld as the the engine never goes over 230 or 250 degrees. Mine runs below 190 degrees this time of year...


On a serious note and back to this thread topic:

It seems that the better the threads are the better nipple will hold. It's a shame people cross thread rip the threads out. You only have to tighten the plugs so the crush washer seals that's it. A standard 3/8 ratchet with a little bit of pressure is good. I believe they even have a torque spec to them if you dont know how to tighten a spark plug on an aluminum head.

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For some strange reason, I feel like I have to defend myself here. I didn't under tighten, overtighten, or strip the threads. I've only owned the vehicle for about 4 weeks. I'm just the lucky one that gets to learn a lot about the engine much sooner than anticipated. While I find the JB Weld comments hilarious, I did, very briefly, consider loc-tite quick metal as a possible short term solution. And I have purchased the '98 4runner that I'm picking up in two days. Then I'll pull the head off of that one and give it a thorough inspection and go from there.

All that being said, I THANK each and every one of you that offers words of wisdom and/or humor. However, lunacy and meanness will be vigorously ignored.

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The heli coil uses the same threads you are installing it with to hold whatever you're installing. The TimeCert has a dedicated set of threads for each purpose.

The procedure for install is the same. But, with the HeliCoil you're just inserting a sprung wire that you're feeding into a hole and then running in a plug.

Think of the time cert as a bolt that you can put a smaller bolt in. Which do you think is stronger.

Yes. I hear you from PO mess ups. Verney and I were just being silly. From what I seen in stripped spark plugs holes the loctite and JB weld arent going to hold.

Any kit that has has new threads that are like a nipple can thread into then you plug will tighten into it be your best bet for holding. As that is what we did in a f350 and it held.

Another option is a replacement head but if it would me that be last resort.

Keep us posted how it works out for you as we like to be informed.



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No defending on this site is necessary or required, period.

Now, I'm curious, was it the right side that blew? That was mine, middle plug.

Mechanic says he's seen them on a few vehicle, different one over the years and attributes it to poor metallurgy in the manufacturing process.

Like I said before my helicoil has held up about 7-8 years, with occasional full throttle highway passing, purrs like a kitten. I'd try that first, its proven to work, less expensive and less intrusive, unless you wanted to do the VC gaskets while at then go for it.

Luck, enjoy and relax.

Yes, it was the right middle plug, and it blew so violently that it snapped the mounting tab for th coilpack. It still runs, just sounds like a Model T. Matter of fact, I drove it 3 miles to my buddy's house where I'll make the repairs.

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I haven't heard of any Toyota blowing a plug by mfg defect until today. Interesting that it's the middle cylinder and these heads on all Toyota engines have been aluminum since the 1970s. Hmm.. I have seen the PO screw up threads on them etc. Just not casting thread issue defect. Very interesting in deed.

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I have a head I can give if your willing to make the drive....but the only good head is the driver side head...but if i recall correctly i think the heads are reversed from each other....so maybe swap some shit around and viola.

Seriously though. you can come take the top of my spare engine and see if you can make something work.

I highly doubt it was you that did the damage. 20 years of spark plug changes from questionable mechanics is most likely to blame. You would have felt the threads give out and the plugs would have started to spin if it stripped when you did it, most likely the damage was already there.

The previous owner of mine burnt the transmission. How the heck does someone do that? At least I get to benefit from a new transmission though. People do dumb stuff and things break and sometime we get to deal with their mess-ups.

Dude, that's an extremely generous offer, but I think that the trip would cost as much as a new head. I'm in South Carolina, where are you located? Tomorrow morning, I'll have an entire spare '98 4runner.

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I have one with a Burnt TC, Blown Head Gasket and Possible Damaged Tranny from 2 PO ago. I think he used really run it. It was a package deal that I couldnt pass up.. The Frame is solid no rust holes at all on a 1997 limited. ;-)

Believe me, some people will find a way..:P

Right, mine blew apart the coilpack itself - so two cylinders firing knocked out instantly. Engine stopped immediately, tried starting but would only spin quickly, didn't try but once. So yeah it was a violent event. Yours seemed to end just a bit better. I don't think its very common but it does happen and its is a manufacturing defect not user abuse, it occured at 194k, now at almost 320, that's how long the helicoil has held. Climbed the Sierra Madres and I-70 west of Denver with ease.

Luck and enjoy your Runner.

Alright folks, started the teardown of the donor engine today. Finally got the head off, however I ran across something a little baffling though. The head was full of burt oil that closely resembles ash. Any ideas on what problems that this engine could have that would cause this?

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