Spark plug blowout

[Dallas Baillio]

Well, it finally happened. Although I am well aware of this problem, I thought I had escaped the possibility in an 17 year old Ford E-450 with 150,000 miles.

Driving on the highway from Fundy National Park to Moncton, New Brunswick I encountered a spark plug blowout. There was a loud pop followed by frequent smaller popping sounds. I pulled off the road, raised the hood and saw nothing obvious. No coolant, oil or PS fluid. I could not isolate, nor see the source of the sound. I removed the doghouse and could feel air being forced out near cylinder # 3. I managed to pull a part out where I could read the part number. Made an Internet search -- an ignition coil.

A motorist passing by stopped and was of great assistance. He called a wrecker for us. This was a Sunday so few sources of repair were available. When the wrecker driver arrived I had to start my BF to shift into neutral for the tow. The wrecker driver heard the sound and said "Sounds like a blown spark plug to me." It was an hour tow to Moncton. The wrecker driver suggested we tow the BF to the Ford dealer saying. "I have towed this problem many times to the Ford dealer and their mechanics have repaired lots of blown plugs."

We spent the night at the dealer among many different Ford vehicles waiting for repair. Monday morning I was at the service department at 6:30 am when they opened ---- their first walkin of the day. The mechanic started the repair around 7:30 and finished about 11:15. $453.13. The tow was $400 but I expect to be reimbursed for that by USAA.

I feel fortunate that this Ford dealer was willing to work on a motorhome. You never know if they will help you or turn you away. I have encountered both in my travels.

On the plus side the guy I met who stopped to help has become a friend. He was very helpful. As payback we took him and his wife out to dinner that Sunday Night. Canadians are nice genuine people. It is really fun to visit here.

Now just 9 more blowouts to go.

[John S.]

That worked out well considering some of the possibilities that could have occurred.

[troutman1971]

So I have heard about this problem from my father who also owns a 2005 Born Free. Is there a recommendation on when to have the sparks plugs replaced or an interval for replacement to help prevent a blowout?

[whemme]

Mark,

If your V10 engine has the earlier type aluminum heads with only 3 threads holding in the spark plugs, then the blowout problem can occur at any time. Installing new plugs early will not change the problem in my opinion. Ford's recommended replacement time for spark plugs is at 100,000 miles.

My V10 has the problem heads and I had my Ford dealer install new plugs at 98,000 miles. I am probably somewhat lucky because currently at 104,000 miles I have never had a plug blow out.

If you want to install new spark plugs, recommend that you have a mechanic experienced with changing plugs in a V10 do it because of the risk of stripping out some of the threads in the aluminum heads.

[MarkB]

I think the blowout issue was from '99 thru 2004 from what I have read. Makes you wonder how the other 9 are doing......

[Dallas Baillio]

What action should I take regarding the remaining nine spark plugs? Give me your thoughts.

I have read that a contributing factor to spark plug blowout is either under or over tightening. All plugs, but not ignition coils, were changed in February of 2013 at 105,750 miles. Plugs and ignition coils on plugs 1, 5, 6 and 10 were replaced in December of 2013. Initial changeout was by an independent mechanic in my home town of Mobile. The second partial changeout was done on the road by a Tallahassee, FL Ford Dealer after my Scan Gauge showed two codes related to engine misfire. I have no idea if either mechanic over or under tightened the plugs.

As I said above the blowout was on cylinder/plug # 3.

I am at least 2,000 miles from home at the moment. I could visit a Ford Dealer and have the torque checked on my remaining nine plugs. I could have them all replaced. I could do nothing (what I have been doing so far) and hope for the best. After all, that is what I have been doing since December of 2002 when I bought my BF used with around 20,000 miles.

So if it happened to me once does that increase the chance of another failure? Or is it like playing the lottery -- no mater how long you have played the same numbers without winning, your chances are always the same with each draw, Those of you with a Ford in the year range of this problem could have it happen to you. My and your odds of a spark plug blowout are probably the same.

What should I do?

[whemme]

Dallas,

Kind of a difficult decision since you already had all 10 plugs replaced once and then later had 4 plugs and coils changed. If you trusted the mechanic to have properly torqued the plugs he installed then I would not take the risk of having them retorqued again. However you then later suffered a plug blows up - if that blowout was caused by that plug being installed with the wrong torque, then you may wonder about the installed torque on the rest of the plugs. I guess it will have to be your call on what to do.

When I had all 10 of my plugs replaced at 98,000 miles by an experienced Ford V10 mechanic, he advised me to also replace the coils as he said that in his experience I could expect coils starting to fail after 100,000 miles, so I had all 10 coils replaced at the same time. Only problem was that each coil cost was $97.50 - Ouch!

[Roger H]

What action should I take regarding the remaining nine spark plugs? Give me your thoughts.

So if it happened to me once does that increase the chance of another failure? Or is it like playing the lottery -- no mater how long you have played the same numbers without winning, your chances are always the same with each draw.

What should I do?

Dallas, you've pretty much described the situation. Each plug in each engine is it's own set of circumstances. Just so you don't think that Ford has the market cornered on spark plug problems, I once had the core melt out of a plug in a Toyota 3.0 6 cylinder while I was towing a travel trailer... granted it's a different issue, but the result was the same... I was stranded on the road for a while.

Replacing a plug at this stage is no guarantee that you won't have another failure anyway; and removing and re-torquing any of the plugs just gives the stock threads one more opportunity to weaken and fail. It's my understanding that, generally speaking, the issue is fixed with the helicoil repair, but that's costly to have done when it's necessary as well. Were it me with your coach, I'd make sure I've got a good towing plan, and just continue to drive it until something else fails.

[karls]

My 1998 E-350 RB blew a plug at 120,000, luckily #5 the right rear one which is the easiest to access.The good old boys in TN installed an insert (don't use a Helicoil) and at 226,000 she's still running great.

An excellent resource for this Ford problem is: blownoutsparkplug.com The website is offered by a Ford master mechanic in CA. They will come to your location and install inserts whether you have blown a spark plug or just want to insure you never will.

The probelm was solved by Ford in 2003 when they increased the number of threads in aluminum heads from four to 10. Incidentally, this problem also plagued all earlier Ford V-6 and V-8 engines.

Talking to the Chief, Rick Mahlmeister at BOS.com was very informative. For one thing, he suggested using 35 ft/lbs of torque on the plugs rather than the 17 ft lbs Ford specifies. As an experiment he torqued a plug until it stripped the threads on a non-useable head, and it took more than 100 ft lbs to do it. 35 rather than 17 makes in less likely that plug will loosen and hammer its way out.

Losing one plug doesn't necessarily leave you stranded. The vehicle can be safely driven with one mandatory adjustment and another that reduces the racket of the missing plug. The mandatory item is to unclip the fuel injector clip on the bad cylinder. This is easy to do and must be done to prevent raw gas from washing away the lubricating oil on the cylinder walls. The other modification is to insert and tighten an expandable plug in the spark plug tube the coil was sitting in. So I carry one of these inexpensive gadgets just in case. That way you can drive home on nine cylinders and hardly know you are missing one.

As for coils (one on each cylinder) going bad and causing ignition missing, if you have a say in it there is a huge range in prices for new coils. I bought six online for $7 each after reading all the comments and deciding to give it a whirl. No problems in 8K miles so far. ( I had replaced the other four earlier.) Access is not easy, especially the center six, so be prepared for frustration.

Karl Striedieck

[Mike Jean Bandfield]

I'd check torque to insure the plugs were at least as tight as spec'd but I wouldn't move them unless they were under torqued. If they are under torqued, loosen them 3/4 turn, start engine and idle it for ~30 seconds to remove carbon that might knurl the threads, remove the plug and put the new one in with Ford recommended anti-sieze compound and torque to spec. Calibrate your torque wrench first. (This is one of those few times I'm happy to have the diesel!)