@SavvyFit I'm Glad it worked out OK for you. You never mentioned which cylinder it was. Was it 3 (seems to be the worst) or 2 (a close second)?

 

Haha thanks! Same, I’m very relieved.

Oh yeah! It was cylinder #2 (counting left to right, correct?). I’ll also update that poll thread now that I know the full picture.

I just drove to the grocery store 10mi round trip, including highway speeds, and it ran fantastic. I’ve still got some work to do but I’m in ‘bidness.

 

Left when standing in front of the car and looking towards the engine. The side closest to the passenger tire is 1, then 2,3 4 heading towards the driver side (for the USA where the steering wheel is on the correct side).
3 was almost out on mine, and 2 was loose. Guess we both got lucky!

 

I'm impressed. I would have thought that the metal of the spark plug would be too soft to do what you are asking it to do.

 

Never buy a thread tap again! Learn this one trick that mechanics DON'T want you to know!!!

I just figured I'd try it.. rather the tap be too soft and get damaged than too hard and damage the hole/s if it doesn't fit right.. which I've also done

Also, super glad this story had a happy ending!! it's been a satisfying reversal on the more common trope: under-prepared, worst possible outcome

 

That is truly awesome. It's hard to see back there so I can understand the mis-diagnostic but still... Great job.

 

So uhhhhh I heard a familiar noise while driving down the highway and immediately pulled to the shoulder. I popped the hood and whaddya know? The same plug ejected again. This time it blew clean out and snapped the new coil pack I just replaced last time.

I’m confident I tightened the plug correctly so I’m a little nervous. I’m waiting for a tow home and I’ll check things out in the morning. I feel like it somehow wiggled loose again, and still didn’t blow out threads, because from what I can see the threads are still totally fine and the cylinder looks clean. I can only see so much with a camera+light though. We’ll see.

 

How many miles did you go? Also, did you use a torque wrench? If so, how tight did you go?

 

Oh, I’ve been several hundred miles easy, probably 1k or more. No issues since, until now.

I don’t have a torque wrench small enough, mine is a 1/2” drive, I tightened by feel/experience. I know experience isn’t the same as a torque wrench, but I’ve been wrenching for 15yrs (I sound like a know it all a*hole but I’m not I promise!) and I also installed/replaced all 4 plugs new at the same time. I checked and the other 3 are still tight.

My guess is whatever grease residue was left over from my tap, must have helped the new plug wriggle loose enough to blow.

I made a tap half a hour ago from a backup used plug with good threads, same as previously, and I couldn’t get it to bite. Even with a little grease to catch any shavings from tapping it. Before trying a tap plug and grease, I did try to finger-thread a used plug I kept with good threads. It bit for a second and it jumped loose (still using fingers then), and the thread on that plug flattened for a few mm so it was going to cross thread. Point being: if I can get weight behind the tap plug, I should be able to fix the threads.

I got it parked safely so I’ll tackle this in the morning. I’ll probably take off the wipers and that cowl piece so I can get a proper look.

 

Damn it!.. I'm glad you'll be getting eyes on it. A hairline crack can hide easy, or not reach upper/visible threads. I think a trick I may have used to check for cracks was.. around the plug hole, using a pencil to draw on the area. There's probably a better way to do that but I noticed when the pencil caught, and if there was a crack I'd wind up with a dark graphite line after going over it enough.
Another thing I'd suggest *trying* to see is the threads. They can crack half way down and go horizontal. If you can't fit a finger or eyes in there, maybe give the hole a chase and afterwards try threading in a wadded blue paper shop towel. if there's a gap the towel will likely lose a chunk in it, leave it hanging there like a little flag. None of these are really good methods 🥲 but the underlying spirit here is that i think at this point you'll want to be positive that there isn't any damage you're unaware of.

So sorry this is happening, dude.

 

Thanks for all the advice! Getting the wiper cowl off was just as painful as I was afraid it'd be. lol
I tried the paper towel trick since it was the easiest to start with, and the plug walls are smooth. I'm confident there's no vertical crack. The plug threads are too recessed for me to get a proper look, but I didn't give up on that yet.

I ordered a replacement plug, coil pack, and 14mm plug thread chaser from Autozone. Same day delivery, by 6pm, so I'm just waiting on that. I always prefer to buy OEM but this will do for now. We'll see what happens. 😅

Edit: Oh and I didn't update here today; I got the wiper cowl off and have a lot more room to work with. I still couldn't get the DIY plug chaser to bite, so I'm trying a chaser kit that comes with a tap and several chasers. I'll try chasing with that first, then move to the tap if I have to. My largest tap on-hand is a M12-1.25, I don't have a 14mm already. Nevermind, the kit arrived and it's an insert kit not a chaser and tap. The site had literally 0 info just a photo. I don't want to use an insert, because that's a lot of metal shavings..
I'll figure this out later my brain is tired.

Thanks man, it's all good, life goes on. I'll figure something out.

 

I would suggest installing a spark plug repair kit/time-sert not a heli coil or it will keep happening. The decent repair kits come with a tapered tap that uses the old threads as a guide for the new ones on the insert. I did mine in about two hours it’s never failed in years and hundreds of thousands of kilometers.

 

Hey thanks for chiming in. Do you have a photo or reference of some sort you could share with me? It honestly sounds like you're talking about what I accidentally bought (thinking it was a tap/chaser kit).
Is this what you're referencing essentially? https://www.autozone.com/test-scan-a...kit/265137_0_0

My one concern with tapping to a slightly larger size, for installing the insert into the spark plug hole, is the shavings possibly falling into the cylinder head. But I did check earlier and found the inserts are threaded the same pitch, just slightly larger of a diameter than the plug itself. So if it follows the current threading, and is cutting the same pitch, then enlarging to a slightly larger diameter won't produce as many shavings I'd imagine huh. A little bit of grease on the tap should catch it.

My mindset right now is "get a plug back in securely, use a tiny bit of red loctite, and it'll run long enough to trade it into a dealer in <6mo. But a more permanent/safe fix is great with me.

 

I used a kit from Amazon WINTOOLS 26pc Spark Plug Thread Repair Kit M14 x 1.25 with Metal Case https://a.co/d/iqrWq76 but I used an insert made time-sert not the crappie ones that came with the kit, with this tap you can hammer it into a socket so you can get it really deep. The one you showed might be hard to use because the spark plug tube is so deep, when you’re cutting the threads just coat the tap in grease and the shavings will all stick to that. After I cut the hole I cleaned the threads and put red loctite on the insert before installing it and let it sit for a day before I started it.

I’ve attached a picture of my actual kit and the tube after it was repaired.

 

Thanks, cutsheal5! I appreciate the photos too. I've done helicoils plenty before but never an insert from any manufacturer at all. I did some research and I see the gnurled edges on the good inserts, with the tap tool you mentioned. They look the most reliable.

I'm definitely not installing one of these Autozone inserts haha. Too bad I opened the package and can't return it; I'll just save it for a less important engine one day.
I'll have to order a Time-Sert, like you did; I see they have the best history/reviews in general. I don't have an air compressor to blow out the cylinder head, so I may just use a 'lil bit of grease. I'll figure it out.

 

If you order the tool from Amazon that I shared, you can probably just goto any local machine shop and get the good inserts from them, they probably won’t even charge you for them.

 

Oh nice, thanks for the tip! I didn't know about that option. I've never interacted with an actual machine shop before, I've always done whatever I needed really. So I don't know much about machinists; that's good to know.

Before pulling the trigger on a thread insert, I ordered a cool little borescope that'll arrive Wed. I also ordered a "Back-Tap" that arrives Wed as well. Depending on what I see with the borescope, I'll decide best course of action then. A small part of me is concerned some of the head's plug threading might have just been completely ripped out and it looks clean and good but actually isn't at all. I'll cross that bridge when I get to it.

 

Even if there is barely any thread left it won’t matter, it will just make tapping it for the insert easier. My car had almost no threads left when I did it.

 

Ah man that's good to hear. I appreciate the help.

The boroscope is going to give me a much better peace of mind, with both the current condition status and after when checking for shavings from a tap/insert.

 

Just remember to put lots of grease on the tap, likely any small shavings will just go right out the exhaust anyways. Let us know how you make out with the job 👍🏻