Loose Spark Plugs? Not Mine.
 

Just thought I'd add my data points to the collective group think.

Yesterday, I changed the spark plugs on my 2013 Fit. Approx. milage: 57,720. This was the first time the plugs had been changed. Point of interest: The factory had put in the NGK plugs.

None of my plugs were loose. In fact, they were in there mighty tight, and I could barely break them free with my girlie but really very attractive hands. (On one cylinder, I had to use an extended handle on my rachet wrench.) The plugs looked great and clearly did not need changing, but, given how hard it was to remove them, I have the feeling that they were on their way to being completely seized.

With regard to the loose plugs story: Do we know how many of the loose plugs were service replacements and how many were original from the factory?

I would have liked to know this with mine. Bought it with about 50k on it and never checked or changed plugs up until it was totaled at 93k miles. Was I lucky? Were they replaced or checked before I bought it. Came from a dealer (not Honda) so maybe they pulled the plugs to check them out.

I think there were claims of a few loose factory spark plug issues, but honestly, I think the issue is AFTER initial replacement.

As I've mentioned before, my theory is that the threads on the spark plug are exposed to build up inside the cylinder which then damages the thread on the engine block as the spark plug is removed.

I mean, my factory spark plugs were very tight on my engine when I removed them at 134k miles/8 years, but the replacement spark plugs came loose shortly after, got re-tightened and ultimately failed less than 4 6 months later (came loose again and broke the ground electrode). The next replacement lasted only a month before coming loose and then spending money on yet ANOTHER replacement after that, only for that one to come loose within a few weeks also. I finally gave up and re-threaded the cylinder and it hasn't come loose since.

Edit: I just went through a few of my previous posts where I mentioned my issues and saw that the spark plug was replaced by the dealer around end of Sept. The initial symptom of sputtering out occurred a few times for only one day at the end of August. I then forgot about it until end of Sept, where I ended taking it to a dealership.

I bought my '11 Sport AT new (11 miles on it) and the Check Engine Light came on at 37,642 miles but I was getting the odor of gasoline on cold morning start-ups for a week or so before that. #2 & #3 were the loose ones. I replaced with new plugs thinking that a new crush washer would keep them tight if I used the spec torque but it didn't and #2 & #3 worked loose again. That's when I used some blue threadlocker (Permatex paste) and good so far at ~77,000 miles on the unit now (~40,000 miles later).

Last year a Bernadi Honda dealer tech told me they looked at spark plug replacement around 100k miles. Given how difficult and expensive it is to change the plugs on this economy car, there are probably not many people changing plugs before 100k unless they have issues or are trying to address the loose spark plug issue.

We see several recent posts on this forum documenting that Honda recently increased torque spec on spark plugs (discussions with Honda dealer techs & photos before/after of Honda tech manual). Why would Honda boost that spec?

There are a few recent threads here of people changing spark plugs to address the loose plug issue. On a 65k mile 2011 Fit Sport we seemed to have a slightly loose plug on #2 or #3 (we didn't measure torque of original spark plugs but used a lot of torque wrenches in school). There are several posts on Fits with blown out spark plugs. I didn't count or analyse the number of people with issues but sensed an obvious problem.

The repair of blown out spark plugs is expensive & difficult for the DIYer (we had spark plug blown out of a GM car last year). So changing Fit plugs and using new torque spec was cheap insurance from our point of view.

Note the max torque specs for a typical alu head are not so much higher than the new Honda spark plug torque spec, so use care. If you have never used a torque wrench, practice at that range a bit beforehand.

The threads on my spark plugs were clean. Shouldn't I see some evidence of this "build up" you speak of?

What's your definition of "clean"? Why not post a picture?

Are these "clean?"

https://cimg4.ibsrv.net/gimg/www.fit...0028108b0c.jpg
https://cimg7.ibsrv.net/gimg/www.fit...14c7af961b.jpg
https://cimg7.ibsrv.net/gimg/www.fit...9645fe7102.jpg

First two are the same spark plug from my initial change in March 2018. The third is from a short lived replacement in December (the third one I mentioned earlier).

Regardless of whether they're considered clean, it's clear that part of the threads is exposed to the cylinder's combustion.

A very close friend of mine had #3 eject at 109,000 miles. They were the original factory, never changed plugs.

That resulted in calling me so I could pull the cylinder head off and take it to a machine shop to be repaired correctly.

Do whatever you want with your Fit's. I don't buy used cars so I don't care. As for our Fit and my Mom's Fit, I'll keep changing the plugs at 50-60k intervals. My friend didn't listen to me and that cost him $$$ and me a weekend.

This was my major concern when I bought my GE8 last month, so immediately after purchase I bought plugs/coils and replaced them. All of my plugs were tight and looked good, but also looked original. Coils were all clean (no soot) too.

edit: oh god i thought this thread was recent when i posted, whoops

So what drove you to do this if everything was working / plus clean / no soot?

My friend and I were on a trip and his car shot a plug out of the head at ~100k miles. His car was running mint and was always maintained other than plug replacement. I didn't know what kind of maintenance history my car had when I bought it, so I always feel it is good to baseline everything, especially at 150k miles.

I purchased my 2010 Fit with 130K miles. No record of spark plug replacement...records showed lots of other maintenance. (but no plugs)
Now...I have 230K miles on it. Am I going to take a chance of spark plug thread failure by replacing them? Hell no.
The car runs great...40mpg.....why mess with a good thing?

Mine came loose at about 240,000 kilometres I replaced all of them with oem plugs, 10,000 kilometres later #2 blew out. I repaired the threads it was not hard nor was it expensive. I haven’t looked at them since, I’m almost at 300,000 kilometres now and I don’t plan on touching them until it happens again lol

I'm planning on replacing the spark plugs soon in our 2013 at 100K Miles. I often have trouble disconnecting automotive electrical plugs -- there seems to be a "trick" with many of them. Is there a trick with our coil pack connectors I need to know about?

We bought the car used and I checked the plugs at 60K Miles and they were tight. (I ask the above question because it was four years ago I checked the tightness and I've forgotten all of the details on how I accessed the plugs.)

I plan to go with 21 LB/FT with the plugs upon replacement.

There's a voice inside of me that's suggesting I simply check plug tightness again and it they're tight, just leave the old plugs in place and not invite a ruined engine trying to do the right thing. This is such a stupidly frustrating problem. My '06 Nissan Frontier 4.0L V-6 takes the same plug size at 18 FT/LB factory spec and nobody has ever had a problem with them loosening.

I've never heard of anyone 'doing major damage' to a car by not changing plugs.
I've heard of many 'doing major damage' by changing the plugs.

roll the dice

I meant that changing my plugs could set them to eventually loosen and destroy my head as they make an exit. The old plugs are in place now and likely tight at 100K Miles.

Data point: one of my plugs ejected itself at 70k miles in 2017.

Had never been changed, known car from new.

My good friends Fit ejected the factory installed plug at just over 90k miles. I would do the plug change.

I second the plug changing motion. I’m the original owner of a ‘12 Sport. I lent the car to my brother who experienced the CEL and code P0302.
His Honda dealer diagnosed “found coil burnt and spark plug backed out of cylinder.” Mileage on 11/17/20 was 55,541.
I only got the car back last week and found this reviewing the service history.
(I’m sure glad I didn’t pay $190.21 for one COP!)

my 213 Fit threw a code, then went into limp mode.
Auto zone read code, as bad coil.
1 orig plug loosened up