Hi bgy692002,

You said it happened near home: did it blow while cruising at highway speeds (55-60 mph), or after getting into the city (25 mph)? Was there a stoplight or other slowing encountered before it failed? What speed were you travelling when the plug actually blew?

It's important for everyone to remember that thread weakening takes quite sometime to occur, and once you get past a certain level of damage the threads will fail and the plug will blow, given the right combination of stressors.

I'm not saying this IS the only possible sequence in which the problem manifests, just that perhaps there's a time when the problem of weakened threads is more likely to manifest, with the thread bore expanding due to excess heat accumulating after driving at highway speeds, then idling, then resuming driving.

It would be interesting to see heat thermal imaging studies of the engine and head under different conditions to see if there's problems with heat flow that might explain the problem (but what do I know: I'm certainly no thermodynamic engineer, although that's what this problem sounds like).

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bgy, my plug never rattled or tapped, just emitted a slight hissing sound, especially noticeable when shutting the engine off and starting.

I'd have a competent mechanic look at those threads and plugs, since it could be the same thing. Perhaps the heli-coil is not as leak-free as it should be? Or another plug bore thread going bad? All eight of those plug bores are only as strong as those of threads of the weakest bore.

Apparently, it's not that easy to check it out these sounds, as there's been posts from people who've brought their F-150 to a mechanic to investigate, and nothing was found to explain the sound (attributed to an exhaust leak). A week or so later, and a plug blows.

Chris

 

It seems I was luckier than most of you. I have a 98 F150 XLT 5.4 with about 53k on it. The check engine light had been coming on intermittently but I had not noticed any other symptoms...I guessed a bad sensor was probably the problem but had not had a chance to check into it. I heard a loud pop then all hell broke loose. I immediately pulled into a service station and noticed that a coil housing was cracked. The mechanic ordered a new one and replaced it saying that the plug had loosened and eventually smashed into the coil housing cracking it. He said the threads were ok and sent me on my way....only $150 for part and an hour of labor. I have noticed that the truck now seems to be idleing roughly at times...dont notice it at higher speeds. Not sure what to do about it though....someone suggested that since the battery was disconnected the computer might have to recalc its data...wait a few days before doing anything. Any thoughts on whether I am tempting fate by continuing to drive it? runs ok...just an occasional hiccup when idleing. The mechanic told me the check engine code was for loss of compression and o2 sensor...he reset it and it has not come back on...only 50 miles on it so far though...should I have all plugs replaced and go from there? Thanks.

 

i was still on the highway doing about 60mph when it blew.i thought it was a tire at first.We got the truck home and the plug was blown but the threads were still intact.when we put the plug back in and started the truck thats when the threads blew out with the plug.For a week befoore this happened i heard a high pitch whistle under the hood i thought was a vacuum leak.The engined was tapping for about 8 months.

 

Update

Well I got my truck last night all the holes now have heli-coils in
them and have changed the plug type to the long reach plug.
Seem to run fine. This was a costly job $2400.

I hope this works .


Abarth80

 

And that's part of the problem with Ford not recognizing this issue or providing any direction (in the form of a TSB): everyone is getting different repairs done!

I paid approximately the same amount for my repair, but only had the one damaged head bore helicoiled; all plugs changed, but they were not long-throw (although I'm not sure how that would make a difference, since it's the thread depth that matters?).

FWIW, my truck idles rougher at start-up than before the incident. Dunno why, but it's a bummer; used to idle nice and smooth....

Chris

 

Thanks to all for the great info. I experienced the same problem on Cylinder 2 at around 80k. Not knowing better, I replaced it and kept driving for another 30k. It happened again, and I replaced the ignition coil and plug realizing it didn't feel quite right. Unfortunately, I didn't think to check the message boards until it left me stranded and completely stripped out. After the usual fruitless call to the dealer ($3100 for a new head), I called some local repair shops about a helicoil. Some wanted to remove the head to do the work ($800), but I did find a local shop that did the work without removing the head for $120 total. I'm very pleased with the result. I have noticed it runs a bit rougher and idles slightly lower than before, but I'll have to get a few more miles before I can troubleshoot it. Thanks again.

 

The mention of scoping the cylinder head and finding what looks like a broken piston is something else entirely. This would NOT be a cylinder head problem if it turns out that part of the piston skirt is breaking up and being busted against the top of the cylinder in turn knocking out the plug. Even a cylinder head with twice as many threads would have a hard time holding up to that. But in any event, I think the number of threads on these heads is not enough. I was surprised that the Lightnings use the same cylinder head.

I guess there are quite a few who don't have a piston issue and this would be a cylinder head problem.

What is the cost in Canada of the head alone? Can you buy bare heads and move your valves, springs, lifters, cam over to the new head?

 

Hi,guys ,I thought i would ad my two cents worth(what i think,not what this pile o crap ford is worth)My truck has 120,000 km on it(approx 70,000 miles)and I had the same spark plug problem,The truck was running fine and then Bang,chug,chug chug,this all happenned at low acceleration from a light,I thought it was wierd as the plugs had been in since approx 60,000 km,,I thought i got off easy at $400 in repairs,then i decided to check on here,
I think i will sell.it after reading that it is a common problem
First the door crack problem ,that my dealership denied knowlege of (of witch I said bs,and told them to check out 150 online) to witch they just laughed(i got the last laugh when they(Zepyr ford,Vancouver went out of bussiness )
Any how ,this truck was the first new truck i have ever purchased
and i have babied it since day one,but i can honestly say ,that after owning numerous fords ,this will be the last
Not only because of the poor quality ,but because of fords denial that these problems do exist ,Please ,if anyone has any info on any class action against ford on these problems,please get in touch with me
Built ford tough/ not tough enough
Chev/like a rock,Ya if i had a rock big enough ,i would crush this pile of ford ,and collect the insurance money,so i can buy a chev

 

It probably stands to reason that the big three and other vehicle manufacturers are building vehicles to last 100,000kms and then crap starts happening... just when your bumper-to-bumper warrantee runs out. I don't think Chev or Dodge is any different. They've got your cash, so f*ck you! (their attitude).

My brother's 1992 VW Jetta has 302,000 kms and has had front brakes done twice, clutch replaced, front struts/bushings replaced a couple of months ago and rear shocks. Last week a friend (ex. VW mechanic) replaced the clogged heater core. Other than that it runs and runs and runs. You're talking about $1000cdn in repairs in 10 years of ownership. Oh, I forgot new tires but that's it.

All new vehicles should be that good and many Honda, Toyota vehicles are. My father has a 2000 Jetta TDI and it drives pretty nice. His computer malfunction light turned on last week. Needs some $150 wiring harness replaced to the glow plugs... wouldn't you know it, 4 months after the 2 yr warrantee runs out. Small price to pay I suppose.

 

Just wanted to say hi.. Im new to the board. Also im having problems with my f150.. I have a 99 f150 with the 5.4. ive blown out 3 different sparkplugs at various times. the latest one i blew out was the #4 cylinder which i had heli coiled since i dont really want to spend 2600 bucks on a new head. Also both heads are doing this so im basically might be stuck with buying a whole new motor. Ever since the last one happened about 3000 miles ago my truck has been pinging really bad especially when in overdrive. Its never pinged before so im wondering if theres other damage? Running super unleaded helps a little bit but not much. Also the truck now surges when in overdrive on the freeway.The truck has 83,000 miles on it and im about ready to sell it im so fed up. Ford will do nothing to help me out so im ready to buy a chevy.Any thoughts on what else could possibly be wrong? thanks

 

Hi all,

The NHTSA released their list of safety recalls for Sept 2002. Amongst other items, you'll see a recall for certain GM vehicles:

Defect:__On certain sport utility vehicles equipped with rearward folding head restraints on the second row seats, two potential pinch points exist on each of the folding head restraints when the restraints are folded rearward as the seatback is folded down._ If a person were to insert his or her finger into the pinch point when the head restraint folds, it could trap and pinch the finger, causing injury.

Well, at least we all can rest soundly at night, knowing our government is protecting us from manufacturers selling unsafe vehicles that could pinch fingers. After all, engine failure due to blowing plugs couldn't be a safety hazard perhaps more significant than a pinched finger......

The bright side is one recall was for a model released by Volkswagen in 1996, since apparently this process may take some time (and a death or two) to get it addressed. The time limit for recall is 8 years....

File a report with the NHTSA, if you haven't done so yet. Anything less is just venting on some bulletin board and will collectively get us nowhere.

It may be pointless, anyway, but do it:

http://www.consumeraffairs.com/news/...often_late.htm

Chris

 

I didn't think there was a time limit on recalls. Maybe there is, learn something new everyday.

 

well it just happened again tonite! same one as last time and i had it helicoiled so im guessing now its time to replace the head. i found the sparkplug that got blown out and the tip was completely waisted. looked like it had been melted off. its getting towed to my mechanic in the morning and hopefully he will have a solution without me having to buy a whole new head.. wish me luck.. oh and by the way this will be the last ford i ever buy

 

Hmmm, the plug tip was destroyed. Thats the first I've read of somebody else having that symptom other than myself. I hope no pieces of the plug fell down into the cylinder. Thats what I had happen and it destroyed the piston and wall. It is very visible with a scope if you can get someone with the equipment to do it. I just went over a 1,000 miles on my new long block and all is well except for that dang rough idle. Good luck.
Mike

 

I posted this in the new "blown plug" thread and here's a copy for those with blown plugs. Another fix option to consider:
https://www.f150online.com/forums/sh...threadid=95825

You may be on to something here. If the end of the spark plug was literally melted off then there is a big problem with the fuel injection/ignition computer control and/or sensors in my opinion. It seems the wrong fuel/air ratio could induce extremely high combustion temperatures. Running lean (nitrous oxide does same thing if not enough fuel is added).

Is there a flaw with Ford's engine management computers, hardware/software??

Something sounds fishy.

Too bad you didn't have a laptop computer in the truck hooked up to the computer running www.obd-2.com software! That may have pointed out the problem.

What I'm saying with head repairs is because I've seen cracked VW type1 (old beetle) heads repaired by welding. These were aluminum too. They welded them up real good, lots of extra material, then the machine shop cleaned them up to spec again. Ran like new. Since the spark plug hole on these engines is so deep I'm sure there is plenty of room to add some aluminum in the hole so there's an inch of material instead of half an inch, the plugs are long enough, this would use all of the threads in the plugs v.s. only half the threads. I wonder why Ford went with only half the thread depth seeing as they have all that material to work with. Whoever the engineer was that signed off on that should be kicked up the a$$ in my opinion.

I don't have any problems with my truck but I feel sorry for you guys. Check into aluminum specialy welding shops. Somebody should be able to do this fix in your area.

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Edit: I wonder how these taper-fit plugs stack up against the usual crush-gasket type spark plugs in terms of gas leakage?