Ford Spark Plug Problems?

j-d wrote:
Thank YOU!!!
Were any of the threads difficult or questionable?
Thanks again, for taking point on this, and the time and effort to produce the narrative and pictures.
You Da Man!!!

Not quite sure how to answer your question, but I'll give it a go.

I used some PB Blaster on the #5 plug that I took out a week or so back to get a match with the replacements. After seeing how easily it came out, I didn't bother doing that with with the others. All of the plugs unscrewed easily once they broke loose. I did use the ratchet when taking them out. There was no problem in starting any of the new plugs into the threads by hand. No indication of cross threading. Once in a while I had to back off a little after a number of turns because it got hard to turn the small diameter extension by hand. That cleared things and I was then able to get more turns. On most I was able to turn by hand all the way to the bottom. On one or two I used the 1/4" ratchet to finish the last turn or so. I believe the threads in the heads were in good shape with just some specks of carbon gunk left in them from taking the old plugs out. At one time I had thought about using a small bottle brush to clean the threads, but forgot about that idea after getting started.

The only plug that had any real deposit on the side electrode was #5, which also had the largest gap. I think that was likely the one that was miss firing. As you can see in the picture, all the plugs look clean. No indication of oil or dark deposits. Should be many, many more miles in this engine.

Forgot to mention above that we took the MH for a ride yesterday and the engine runs and idles smooth as silk. DW and I are happy campers again!

A big thank you to all who posted to this thread. Your ideas, suggestions and past experiences were a big help in getting this project done right.

Maybe a moderator could make this into a sticky.

Thank YOU!!!
Were any of the threads difficult or questionable?
Thanks again, for taking point on this, and the time and effort to produce the narrative and pictures.
You Da Man!!!

Our E450 engine is now the proud owner of 10 new spark plugs and 10 new coils!!

As promised, here are my experiences in doing this job. It actually turned out to easier than I had feared. First I removed the seats in the cab to get some room to work. Removing the seats requires a Torx #55 and an 18mm socket.

Access to the area around the coils and plugs is limited but after the heavy wiring bundles that feed the coils, fuel injectors, and other items were moved out of the way it wasn't too bad getting to all the plugs. I did not have to disconnect the wires to the fuel injectors, but did remove the wires from all the coils to get more space to work in. No concern about mixing up the coil wires as they are too short to reach a wrong coil. The cylinders are numbered 1 to 5 front to back on the passenger side and 6 to 10 on the driver's side. I was able to remove and replace the coils and plugs for numbers 1, 2, 6 and 7 from the front and the remainder from the inside of the cab. The most difficult were numbers 3 and 8 because it was hard to get leverage on the wrench in the confined space to break the old plugs loose and properly torque the new plugs.

After the cables and other items were out of the way, I used compressed air to blow as much of the dirt as possible off the top of the cylinder heads and around the coils. After removing each coil hold down bolt (7mm socket and 1/4 inch ratchet worked fine), I twisted the coil and blew off the surrounding area again before pulling the coil out. After removing each coil, I blew out the spark plug hole. I removed all of the coils on the passenger side first, then started removing and replacing the plugs on that side one by one. As I unscrewed each plug, I removed the spark plug socket a couple of times and blew out the hole to make sure no grit got into the cylinder when the plug came out. Overkill maybe, but why not. I screwed the new plugs in just turning the socket extension by hand to be sure not to cross thread. The plugs went in dry, no antiseize. I torqued to 180 in-lb (15 ft-lb). After doing all plugs on the passenger side, I installed the new coils on that side to prevent any grit from blowing off the driver's side from getting into the plug holes. Same steps as above for the driver's side. Now for the pictures.

Cab with seats and doghouse removed.


ZIP ties holding wire cable away from coil spark plug area


Closer view with cable bracket bolts removed


Passenger side from front with bracket bolts removed


Driver's Side front view


#6 and #7 spark plug holes


Passenger side from cab after all new plugs and coils installed


Driver's side with all new plugs and coils installed and wiring cable back in place (tight, isn't it?)


Everything back in place


Motorcraft ignition coil info


Old spark plugs. Gaps were 60 to 75 thousandths with #4 and#5 the worst. New plugs gapped at 54 thousandths.


Tools I used for the job. 1/4" metric socket set not in picture. The magnetic 5/8" spark plug socket with attached swivel extension was the best thing I bought for this job. The swivel made it so much easier to get the socket into the plug hole in the tight quarters.


After doing this once I wouldn't hesitate to replace just the plugs again in 50-60,000 miles.

Thought I would contribute..I have a 99 E 350 and two summers ago had a plug blow out. A guy in Vanderhoof did the job..and it was quite a piece of work. Tapping the hole blind..couldn't actually see it. In with the heli-coil.

I had bought a set of coils from Summit Racing some months ago, too..a just in case thing. At a Ford dealer here in Canada they are $100.00 a piece...Summit was..uhmmm...$100? for 10. Anyway...with 210,000 on the clock I decided now is a good time to change out all the plugs and coils...had the work done here in Penticton. $600.00. That included a tire rotation, by request.


Gary Haupt

CD, the shop I visited, looked our 2002 up by VIN and produced 08-15 ft-lb with NO anti-seize. Told me he'd torque to 15, again, dry. I'm confident enough in what they told me, that I'd go ahead with that torque, but from what you said, pull the plugs with engine cold.

blownstang01 - thanks for your comments.

Would you happen to know the correct spark plug torque value for a 2003 2-valve engine? My plugs have 8 threads on them, but I can't see well enough down the hole to see how many threads are in the head and the internet has a number of different torques for plugs. Hard to tell which engine the poster is referring to.

Thanks in advance

Just replaced the plugs on my '06 @ 46,000 miles...just because I was doing spring maintenance and wanted them replaced. Glad I did, the gaps on the "100,000" plugs was already at .070 up from the factory .054...as you know can cause coil pack and boot issues with the increased gap. The job took me about an hour and a half. The biggest thing about working on anything on these is to not be afraid to move stuff out of the way, a few minutes here saves a ton during the job. For instance, for plugs I removed the airbox assembly, the passenger side lower dash trim, and the two plastic wire supports that encapsulate the coil pack and injector wiring. With the wire supports in place it's very difficult to get a straight shot at the plugs...with them removed it's pretty easy.


WARNING-----Seriously Boring Somewhat Irrelevant Info Follows:

A side not about plug problems, if anyone seen my previous post, I stated that I worked for a large Ford dealer for almost 20 years. One thing we saw in the early modular engines (pre-2002) was spark plug blow-out, mainly due to not enough threads in the heads. Actually, IMO this wasn't even a wide-spread issue, but you know how the internet goes so now all Ford engines have this problem, lol. This (again IMO) caused additional problem from backyard mechanics tightening the snot out of replacement plugs because they "heard" about all these "problems" and the next guy couldn't get those ones out without screwing things up.
Next came the 3 valve engines that had two problems...mostly in F-series trucks. First problem was that the 3-valve spark plug has a long extended tip that originally was two piece...this probably looked great on paper to help plug cooling and packaging, but nobody seemed to realize what carbon build-up would do to the surrounding orifice of the plug in the cylinder head. Yup, you guessed it, carbon buildup would seize the lower extension of the plug and it would break off when removing. This became exasperated when the plug change intervals was upped to 100,000 miles and became the debacle we see all over the internet today. The second issue was on the F-series the engines sit way back under the cowl causing rain water to drip down onto the last cylinders, that would eventually leak past the coil seal and fill the plug hole in the head with water.....rusts the plug...eventually has a misfire due to moisture in coil/boot. Then the plug is corroded and not easy to remove. The advice around the shop was never go more than around 30K miles on plugs if you want to get them out. Ironically, other shops would say never touch a 3-valve plug unless you have to, lol. We had some success in getting the factory plugs out by running seafoam through the engine first to help clean the carbon out. Oh, and always replace with one-piece plugs!
So, anyway after that long winded post this is useless info to Class C guys as the E-series doesn't have that engine, but maybe a Class A 3-valve guy might stumble in some time. Cheers

Thanks everyone, but after reading everything. Looks like I'm not affected by the issue, more commonly seen in non-E series. Especially if they're still OEM plugs. I'll just double check torque and let it be for next 10-15k miles.

Clouddriver, that gap tool is a nice one. It's one of the best I think. I have a bunch of different ones and that one does the gap and adjustment very nicely. For a less expensive setup than the Snap-On socket, it's possible to get an extension and socket that lock together with a pin that has a spring underneath it, similar to impact sockets. I can't remember the brand, but just make sure it can't come apart. If the socket jams, a magnet may not be strong enough to get it out. I do think your duct tape idea will work unless it jams really bad, which I think unlikely. The Snap-On socket is a 3/8 drive and it fits the plug perfectly. The B diameter you mention is not more wide than usual, in fact I think it to be more narrow which is an advantage. You can kind of gently feel the plug drop into position with a slight wiggle of the socket then very slowly start to turn it. If it hangs up you stop, alter the angle a bit, then turn repeat. Be gentle. Once it starts you will feel uniform slight but smooth resistance and you know your headed home.