I've been reading about the coil problems, and had some of the same symptoms recently. Before I had a chance to take the car in (we're pretty remote), BOOM, and the car sounded like a helicopter. Looked under the hood and the coil was blown off, with the spark plug missing. The car has 82,000 miles and I have not touched the plugs. Any ideas on causes and whether I should expect honda to remedy the situation? It also had a slight exhaust/gas smell when at a stop, so I'm thinking the plug had been working it's way loose for a while and finally blew out of the head. I had asked a honda dealer service about the smell and they just said the exhaust was being sucked under the car and back in through the vents. Brilliant.

It's a 2008 Sport AT.

 

Its probanly a result of not touching the plugs for 82,000 miles as you suspect. We've not seen the problem here but none of the vehicles go 25,000 miles without checking plugs. And yes exhaust fumes will mf sucked up under sa vehicvle. A lot of passengers in station wagons with roll down windows or driven with taligate up have passed out from the carbon monoxide in exhaust fumes sucked in.

 

What do you mean check plugs every 25000? What are you checking for?

 

Routine plug checks for combustion quality based on color of the ceramic around the electrode and the gap. The gap needs to be reset about as ioften as valve clearances.
Ceramic black color indicates too rich, light brown good combustion and white too lean.
And of course leakage or bad electrodes or other defects mean replacement.
Spark plugs, like coil packs, don't last forever.

As for transmission oil changes we've never done one on thousands of cars in 50 years and no one tranny failure. Clutches, yes, but noit trannys.

 

You are not the first one to report this plug blow out problem. The last one here was from Ontario or Quebec. Honda refused to help him in any way on his repair and said he had been "tampering" with the spark plugs which he denied.

 

The exhaust smell was coming through the vents with the windows up, so in through the engine compartment. The dealer was suggesting it was travelling the entire length of the car and being recirculated into the cabin. I was suspecting an exhaust leak, and checked for noises and smell with the engine running and the hood up. Nothing unusual or suspect. I imagine this was the beginning of the spark plug working its way loose and allowing some blow by.

Spark plug failure: I realize they don't last forever, but they should last at least as long as the recommended service interval. I don't think I should be blamed for not second guessing the engineers who designed and built the car. Is this plug inspection process part of the normal recommended service, written down and suggested somewhere?

Additional info I should have included, there had been no loss of power, mpg, or check engine light to alert that anything was abnormal.

I suppose the main question is "Should properly torqued plugs work themselves loose or completely blow out of an engine?"

 

Also, if I were to inspect the plugs myself, would this be considered "tampering" as well?

 

And no, properly torqued bolts or plugs should not work themselves loose, however, how many are torqued properly?
Did you know that proper torque REQUIRES that the threads be 'lightly lubricated' with 'proper lubricant' ? Check any SAE or Machinists Handbooks.
As for plug inspection you may want to review pages 3-8 and 4-23 in the service manual regarding the service intervals for various maintenance items. Did you check all those items routinely? In short, checking plugs, belts, valves, fluid levels, boots, parking brakes, brake pads, tie-rods, cat heat shields, connections, etc are just that routine inspections and that's not longer than 12,000 mile intervals.
I find and identify with Dilbert when they make fun of 'marketing' because marketeers ignore the requiirements of engineering to promote sales. And Honda is not nearly as bad as other manufacturers; who's run into "they all do that" ?
Just remembedr, you'rte responsible for your Fit's health and you should take it seriously. Its not maintenance free.

 

I agree with you, spark plugs shouldn't loosen on their own, and they should have been properly torqued from the factory. It's not your fault for not checking the spark plugs at 25k miles or whatever the ridiculously low number was that someone suggested.

It's not uncommon for people to try to distance themselves from others whom something bad happened to, it's just human psychology, an attempt to reassure oneself that the same thing wouldn't happen to himself/herself. This is a pretty good example. Something crazy happened with your spark plugs and now you're hearing, "Well you should have checked them periodically, even though they're good for >100k miles." It's absurd.

Just like any manufacturing process, there are bound to be defects. There have been maybe 2-3 reported incidents of spark plugs blowing out on these forums now, that I've seen. But there are also like >60,000 registered members, so it's not exactly a common occurrence either.

 

I searched for the term 'spark plug' in the electronic version of my owner's manual (2010). The only appearances are:
Replace spark plugs when the MM displays '4.'
The part # of the plugs.
In the index, pointing to the page giving the part #.

So- they can't really tell you it's your fault for not inspecting, can they? Since they didn't tell you to.

And as far as 3 reports out of 60,000 members of this site, is that 60,000 who have joined at one point? How many are still active enough to post?

I know of no reports of windows falling out, steering wheel falling off, batteries cracking, etc. So- 3 reports of spark plugs blowing out seems like 3 more than their ought to be.

 

I agree with you Mike, but it is logical to assume that some Fits do not get the proper torque on spark plug installation at the factory. So, some of us have Fits with improperly torqued spark plugs. However it is really hard to imagine that those cases would result in spark plugs blowing out as the OP has described. But it is impossible to expect the average Fit owner to assume that it is his/her responsibility to check for proper torque on all spark plugs to insure that they DON'T BLOW OUT. What a dumbshit thing for anyone to assume.

 

Certinally not every 25,000. Mabey 60, more like 100,000. Back in the 70's, mabey.

 

My Fit's MM called for valve clerance check at about 110K miles, about the same as the Fit's manual called for spark plug change. The replacement plugs I got specified NOT to be regapped. My expectations may be higher than most, but I expect a new car to be properly assembled (including critical parts being properly torqued).

 

Although Mahout doesn't explicitly say so his message may imply to lubricate your spark plug threads, which is not safe, in my opinion. Check the plug instructions that came with the plugs or use the plugs recommended by the MM and install them accordingly. If you do the latter you will install the plugs dry and torque to a certain value. There's an exhaustive discussion about this in the do-it-yourself forum about plug changes.

 

Its not implied, its a flat statement: thinking you get properly torqued plugs - or wheel nuts - with dry threads is chancy.
As proof, we've always used nickel based hi temp lubricant on both spark plugs and wheel nuts on thousands of vehicles for 50 years without a single comeback or problem. You're barking up the wrong tree if you think the SAE or Machinists Handbooks are wrong.
But anyway why do you think lubricating spark plug threads is not safe? Perhaps you think it interferes with conductivity? Long ago that issue was put to rest.
Perhaps you think lubricated threads unwound easier? Long ago it was found that tightening dry thread was more likely to result in less than specified torque values and under repeated heating and cooling could result in loosening the bolt. Lightly lubed threads torqued better and held tight under the same circumstances.
That of course does not apply if lubricant is slopped on the threads of spark plugs or wheel nuts; I don't know what that does.

 

If its so dumb. why do you think manufacturers refuse to accept liability for owners failure to accept responsibility for their vehicles up keep? How about damages from no tread on tires? Or windshield wipers not working? Or body or suspension damage from improperly lowered suspensions? Or wrong wheel/tire applications? Vehicle owners are expected to do their part in maintaining the integrity of the vehicles, houses, and other property. If you can't do it yourself then take it to someone who can. Dumb is thinking otherwise.
If those plugs blew out in 1000 miles there may be case but not after 50,000 miles.

 

Ooh, the Elephant Man is really cranky this morning. I will make my statement to doctor doom a slightly different way-

It is ridiculous for anyone, particularly any auto manufacturer, to expect the car owner to check the torque on spark plugs and all fasteners (lug nuts, all engine and transmission bolts) to be certain that they were all torqued to the car maker's own specs, simply to be certain that their wheels don't fall off or spark plugs blow out on their drive home from the dealership.

If there were a sticker on the windshield of every new car that warned "We cannot be certain that our assembly personnel have properly tightened all threaded parts in this vehicle. For your own safety, you must check that spark plugs and all fasteners have been tightened to our torque specifications", how many new cars would be sold?

The mere existence of a drive train warranty on new cars is the car maker's guarantee that the car was put together properly and is not expected to have mechanical failures.

Damage that is caused by inept car owners who don't know how to perform simple mechanical tasks should certainly NOT be covered under warranty. Damage that occurs over many miles of use that is NOT addressed by the car owner, such as tire wear and wiper deterioration, would not be a warranty issue either, obviously.

 

Lube on spark plugs/wheels studs not necessary.

 

Well, you ask and you shall receive. I've made this so clear yet a few of you still fight the world on this. Yes, I think lubricating threads is not safe. NGK has made that statement too: http://www.ngksparkplugs.com/pdf/tb-...1antisieze.pdf. If you google "torque specs dry vs wet" you'll find a multitude of information that explicitly shows the difference between dry torque and oiled torque. The larger the fastener the greater the difference. This is especially bad with spark plugs because they are not a solid fastener but rather a shell, so any torquing past what the engineers of the plug have specified you risk yielding the material.

So again, you asked, and here's the guts of it. I didn't look any of this up. I use this in practice. By the way you didn't quote a reference. SAE and Machinists Handbooks are not references. Are you talking about Machinery's by Industrial Press? If so there's an exhaustive analysis of that in that book. Torque values are generally accepted in almost every industry as derived from the formula kfd, where k is a friction coefficient (usually .2). The intent is to displace a fastener to about 70% of its yield strength. If you change the friction coefficient, (oil vs dry) you change the torque spec. "f" is force in lbs or desired preload (the 70% of yield I talked about) and "d" is major diameter of the threaded fastener. So that's where torque specs come from. They are dependent of the friction coefficient.

Those industry standards are passed down from engineers to maintenance manuals that you should be referring to. If th MM does not say to oil a joint then don't. Of course, if it's rusty, use best judgement and maybe oil it. But hardly any fastener these days, especially plugs used on the honda fit, are zinc plated. The torque values were derived from not lubricating the threads. And that is my point, that the torque values for NGK plugs in the Honda Fit are based on dry threads. If you lubricate them you will increase the displacement of the threaded plug shell to an amount it wasn't designed to. It may well work, the extra displacement may still be in the structural margin of the shell, but you are taking a risk. That is the bottom line.

 

^ Here's a reasonable person. Well put.