My '08 TL-S with 92,000mi under a dark cloud.

After 4 years of flawless service, I've experienced a streak of bad luck all within one month:

1. Blew-out a brand new snow tire on an unseen pothole at night.
2. Broke a Left-outer CV joint - I knew there was a hole in the boot, and the replacement had just been ordered, but not soon enough. Had to be towed.
3. Cylinder 3 Spark Plug ejected from cylinder - Just finished replacing half-shaft and was just taking the car out for a test drive and the spark plug went ballistic - the plug ejected from the head and smashed the coil pack - I thought the plug just came loose, but when I tried to put the plug back in, there were no threads. Had to re-tap the head and put in a Helicoil.

Hopefully that's the end of my bad luck streak with an otherwise great car.

 

Whew!! That is some bad luck. Let's hope some GOOD luck is coming your way now.

 

Just a quick question- how was the engine running just before all of this happened? Was there any ticking from the engine or a knock? I would think if the spark plug was loose, it wouldn't seal in the head as well, and the engine might run a bit rough.

 

Maybe someone previously cross threaded that plug in?

 

High-mileage Plugs backing out is becoming a common issue on Honda V6. The Pilot and Odyssey forums are full of complaints. Now they are showing up here as well.

If you plan to run your plugs to the recommended 105k miles, you had better be checking the torque.

 

What has been happening is that the plug backs out, but the threads still seal somewhat. If the hot blowby doesn't melt the coil pack and cause misfires, eventually the threads in the cylinder head will gives way. This is what causes this catastrophic failure.

Like our OP here, the failure can be very sudden with little or no warning.

I did read one thread where the OP heard the noise and caught the problem before it blew out. The coil pack was damaged though and needed to be replaced.

 

did you pull the head before drilling and tapping the new threads for the helicoil?

 

I'm finding most people install the helicoil in place. Meaning the head is still on the block. I know it sounds crazy, but that's what they do.

 

I have 75K on my 06- I guess I'm officially worried about this and will plan on checking the torque- I guess while I'm there, I might as well change them.

 

At 75,000 miles I had a honda mechanic friend change the plugs on my 07' TLS. He found one plug loose and ready to set sail toward the moon. I suggest everyone check their plugs ASAP.

 

BTW that was my thread about the noise, my friend immediately knew what it was. The car had a real bad tapping noise & was the plug nearly backed all the way out. Only 2 turns left on the plug before it would have launched.

 

I had an accord in a few months ago with a blown out plug and coil. I put in a time-sert, plug, and coil, but still had a misfire. On close examination with a bore-scope, pieces of the plug had beaten the top of the piston and also broke several pieces of the top piston ring land off.
After a lot of back and forth with the dealer and honda corporate they finally got a new engine warrantied.

 

Was the CV "clicking" or "popping" before it failed?

What size snow tire, 235/45R17?

 

I hope that my post will find people before their beloved TL meets the same fate as mine. I have 105K on my from-the-factory, never-wrecked, always-maintained to schedule, pristine '05 TL 6spd and was scheduling time to take it into a very good local shop for the scheduled maintenance. At 105,346 miles, #5 spark plug (middle-front cylinder) finally gave up the ghost and fragged the coil. I had it towed to the shop that was already going to do the work. Upon inspection, the threads were toast, as is the piston head, as is the cylinder wall. Upshot - motor is fragged. It's too expensive to rebuild (labor costs). Upon further inspection, cylinder #2 plug (middle-back cylinder) was loose. I'm sure some would just thread the head and quickly trade the car but I still intend to get 200K miles out of my $36K purchase! Please note: Prior to the plug failure, there was NO indication of an issue. Gas mileage was good (as good as you can expect on 10% ethanol) and it ran like a "scalded dog", as it always has. I hope my post finds its way to even just one TL owner - CHANGE YOUR PLUGS EARLY!

 

I just recently replaced mine for the second time (120K miles, first was at 60K) and found that all 6 of the plugs were still snug from when I did them the first time. Both times, I torqued them to the right value and applied a light coat of anti-seize compound.

 

Update -
The car now has 111k mi and the heli-coil is holding great. I did tap the helicoil with the head in place using the technique of loading the tap with grease to catch the filings.

I'm now starting to get some vibration unrelated to tire balance and suspect the right driveshaft will need replacement soon.

 

Thats a common sign the axle is going bad. Even if its just during cold weather while the grease is cold.

 

Its kinda weird Acura's torque spec is lower than NGK's specified range for aluminum heads.

 

No it's not. Honda's spec requires anti-seize (a lubricant) and NGK's doesn't. Therefore the Honda's number is going to be a lot lower.

 

What's the recommended torque for NGK IZFR6K11/6994 plugs?

NGK shows a table of thread diameter vs. torque...http://www.ngksparkplugs.com/techinf...asp#installing

EDIT:
According to some other sites: 14mm -> 18-21.6ftlb (220-260inlb)

I'm going to go check the torque on my today; they've been in for ~2000 miles. I originally used the Honda-spec @ 16ftlb.

 

Here we go again....The TL Service Manual spec for spark plugs is 13 ft-lb, not 16 ft-lb.

 

This!

To achieve a proper preload force F, you should apply a torque according to the equation T = K*F*D (where D is the thread diameter and K is a torque coefficient). The value of K goes down if you use a lubricant. Antiseize lubricants can reduce torque required by approximately 20%. So if NGK specifies 18, then 80% of this value is 14, which is about what the service manual specifies.

 

I did it according to the FSM; I thought it was 16ftlbs, but I guess I was wrong. I must have torqued my NEW NGK plugs down to 13ftlbs w/o anti-seize. I'm going to re-torque them to 18ftlbs.

 

If you're going that far why not pick up a small tube of anti seize and do it to spec. you'd hate for the threads to start galling

 

NGK is specific about not adding anti-seize because their plugs already come plated (zinc, nickel?). I believe that this plating provides the anti-seize property w/o affecting the torque setting.

 

Meh. The NKG bulletin says that use of anti-seize has led to cases of over-torquing, not under-torquing, so I dunno.

Since the Acura service manual calls for the use of anti-seize, I only assume that Honda/Acura set their spark plug torque spec with this in mind (which if you think about it, 13 ft-lbs makes sense).

http://www.ngksparkplugs.com/pdf/tb-...1antisieze.pdf

 

Ok, I read the pdf.

I'm going to torque down my plugs to 18ftlbs (~220inlbs on my torque wrench) since they have no anti-seize on them.

If I remove them before the next replacement interval, I'm going to torque them down to 13ftlbs (18nm; ~160inlbs) w/ anti-seize (specifically, Nickel-based).

 

FYI and FWIW, I just checked my front plugs and they are all fine.

I changed them 21K miles and 21 months ago. Used anti-seize and 13 ft-lbs. They are still snug.

 

I just checked mine (all six); they were all snug and the engine was completely cold. They didn't move at all even with my torque wrench @ 18ftlbs. I'll check them again in a year.

Now, I don't have to worry about my engine ejecting a plug or a clogged A/C drain frying my ECU. I stuck a wire up the drain tube to make sure it was clear and because of the weather, I shouldn't have to use my A/C very much. I do, however, like to run it atleast once a month (even during the winter) to make sure that the oil in the system stays dispersed.

 

Sorry man. IMO it is kinda weird Honda specs the NGK plug, but the instruction differ a bit by mfg for the exact same procedure.

 

I've been hearing a knocking noise for a couple months,at 90000 miles for roughly 5-10 seconds before going away on a cold morning start. I think it's my timing belt tensioner though. I'll recheck my plugs into did 30000 miles ago. I didn't torque them,but they were prettysnug

 

I was planning to do this myself at the next oil change. Where is that drain tube. Passenger side right?

Maybe its because NGK doesn't necessarily know what kind of cylinder head their plugs are going into, but Honda does.

 

Yeah, passenger side near the firewall. Search around in the ECU/water threads. I think someone posted a pic.

 

Hey guys so its 5 pm i head to the garage to get in my car and off I go onto the merit pkwy in CT. I drive a mile on that pkwy and all of a sudden i hear a pop as if my tire blew. I pulled over popped the hood and the coil pack in the center toward the rear was missing. The blue plug however was still intact. That leads me to believe that the coil pack screw that holds it down was loose. I did the plugs myself and i know that i tightened down everything !!!. Or is it possible that something else happened mechancially ? So the tow truck comes and i hook on that tow hook in the front of the car, he starts pulling the car up to the flat bed when bam the hook breaks off and my caf starts rolling back me and him are trying to stop the car from rolling onto the pkwy very scary i have to tell you. If anything what do you guys think might of happened to the coil as to why it popped out ?

Thanks Guys

 

What do you mean by "blue plug"? And the entire #2 coil pack was gone? No pieces anywhere? What about the wire harness for the coil pack?

 

The blue plug which plugs into the black coil and sits ontop of the coil. Im probably wording it wrong when i say blue plug sorry if i am. Im sure the black coil went on to the highway but dude that highway is crazy since people do a minimum of 80 i didnt want to risk my life especially being at the top of a hill so the blind spot wouldnt let me see any on coming traffic. I looked in the engine bay couldnt find that damn coil but maybe its in there in a place not seen by my eyeball. Now you say wire harness wouldnt that be the blue plug that plugs into that black coil ?

 

Hmmm... Is the #2 spark plug still there? Is the allen screw that holds the coil pack in place still there? Kind of strange to me that the wiring plug (blue plug?) is still intact after a coil pack/spark plug blow out, but maybe so.

Did you use anti-seize on the plugs and torque them to spec (13 ft-lbs)?

 

They were the NGK laser iridium plugs which come stock with the car. No i didnt gap the plugs because they come pre gapped already. Yes i know weird that the wiring plug was still there. I checked for the screw too but didnt see that either, i was just looking at the cylinder without the coil in it. I didnt feel for the plug since i didnt have my extension i only had my spark plug extension which wasnt long enough since its in the back you need another extension thats how i did the job. I just hope that there in no damage done to the cylinder bro. I am hoping it was because the nut was loose and thats why the coil popped out. I mean lets say if the nut that holds the coil was loose that would happen right ? Since there is pressure underneath the coil during the operation of the car

 

There is no pressure on the coil. It sits on top of the spark plug. Sounds like the plug blew out. Question is why?

And I asked about proper torque on the spark plug, not gap. And whether or not you used anti-seize on the plug threads per the service manual procedure.

 

oh yes im sorry man my head is a bit clouded im still pondering on how it happened. I torqued it with one full turn and then a half a turn i believe thats correct right ? No anti seize was used. Ok now that we got that out of the way seems that the plug bursted but its possible it wasnt torqued right so maybe it was loose.

I read earlier in this thread that if you hear a ticking sound or clicking sound coming from the engine then its most likely that one of the plugs could be loose. Is that what you call a misfire ?