Finally got around to changing the sparkplugs on my 2009 F250 6.8L with 101000 miles and wanted to share my experience. I purchased this truck last year with 98000 miles on it and this was one of things I wanted to get done.

Since the factory manual says the plugs should be changed with the engine warm (not cold or hot) or you could damage the threads in the head, I ran the truck until the thermostat opened then turned it off. The factory manual says "warm to the touch" so "I" took that to mean I should be able to lay my hand on the head casting without it burning so much I had to pull my hand off.

While it was cooling down I gathered all the tools I thought I would need along with a large piece of thick cardboard and the engine bay support board I had made for doing this job (see pictures below). This board allowed me to do all the work from the front of the truck while supporting my belly/chest. Some people do this from each side of the truck, but I found this way to be better for me and my old aching back. The cardboard was so I did not accidently bump into the front radiators and cause any fin bending. I then stood on a 18" stool to do the work.

Getting access to all the plugs only requires removing the intake housing that goes from the throttle body to the air filter housing. The clamps require a 7mm socket on the throttle body and a 8mm on the filter housing end. Once that was removed I covered the throttle body and filter housing openings with a rag and zip tied the rags on.

Looking at each side of the engine there is a large wiring harness that all the COP (coil on plug) and fuel injector connectors are bundled in. These harnesses are attached to the valve covers by push on plastic supports. There are three on each cover. I removed these supports from the valve covers by pulling up on each. This allowed the harnesses to move away from the valve covers and give a little more room to work.

I took my air gun and blew all around the top of the engine and especially around each spark plug boot to remove as much dust and debris as possible. Fortunately, this engine did not have any oil or gunky stuff around the plugs, just mainly dust and dirt. I pulled all the COP connectors off and tucked them aside.

I did all the above while waiting on the engine to get just "warm".

I decided to start on the passenger side since it has the sparkplug farthest back (cylinder 5 - see picture below) and I figured it would be the hardest to change. I removed all the COP bolts with a 7mm socket and various extensions depending on which hole it was. Starting with cylinder #5 I pulled the COP/boot. I was surprised it pulled out easily. I thought the boots might be hard and brittle after this many miles. I took a small hard nylon brush and cleaned around the top of the spark plug hole where the boot seals to dislodge any debris then blew the hole and around the top with air again.

I then took my homemade for this engine spark plug tool (it is a 9/16" standard, rubber insert spark plug socket that I roll-pinned to a 6" extension), placed it down the hole and seated it on the spark plug. The extension protudes far enough above the hole so that you can get your fingers on it and also allows adding whatever socket extension stuff you need to work on getting the plugs out such as wobble adapters and other extensions. As you can see from my picture of the tools I needed to do this job, I had various 1/4 and 3/8 inch socket stuff handy.

Using only a small 3/8" ratchet I gently started loosening the spark plug. I was surprised it unscrewed very easy (maybe a testiment to the way the shop manual says to do this). After removing the spark plug I gently blew out the hole again. I placed the new spark plug into the socket, inserted it in the head and turned it by hand to be sure I did not cross thread it. I was able to screw the new spark plug almost the entire way by hand. Once it reached bottom I attached my torque wrench to the extension and torqued it to 108 inch pounds (about 9 foot pounds). This is the torque for the newest heads with full thread plugs and brown COP boots.

I had decided to change all the boots at the same time since I figured they would be hard and brittle. To my surprise they were not. They were somewhat dirty around the top but still very flexible. After pulling the boot off the COP, be sure that the spring wire inside is fully seated on the COP connector. I put some dielectric compound around the tip of the new boot (as stated in the shop manual) and pushed the new boot onto the COP. I put the COP/boot into the spark plug hole and seated it on the plug.

I then proceded to do the rest of the spark plugs the same way. After all the plugs were changed I bolted each COP down and torqued those bolts to 50 inch pounds. Now, reconnect all the COP connectors.

Some things I noted while doing this job. I found that plugs 9 and 10 were actually the hardest to change because the fuel rail seems to be a little more in the way. In my case all the plugs came out easily. Have a bunch of extensions handy. You will need them to make the job go a lot smoother. Make sure the COP connectors seat and lock when putting them on the COPs. I rechecked and found the one for COP 9 was not seated fully. I checked the gap on the old plugs and found the largest gap was .048. Not bad for 101000 miles. I replaced the plugs and boots with genuine Ford parts.

It took me about 4 hours to complete because I tried to be carefull in all aspects of this job. It was not difficult and the first time I had replaced plugs on a modular Ford engine.

Thanks for reading and hopefully this will help someone else prepare for doing this spark plug change.

Good luck, Tom



FORD 6.8L V10 - Cylinder Layout

 

Good job!!!

 

Great write up! Thanks for all the details and pointers. I should do mine soon.

 

Nice job, nice write up, want to do mine?

 

We're the plugs original? What shape were they in? When I had my 2000 with the 6.8 I had Ford do the initial plug change at about 98,000 miles and was amazed how well the condition the plugs appeared to be in.

 

Good write-up......best thing is patience! Takes me about 2 hours to do mine.

 

I would surely help if you were close.

It is not that difficult. Give yourself plenty of time.

I assume the plugs were original. As stated, most measured around a .048 gap. The new plugs were gapped about .042, so a .006 increase in gap in 101000 miles is darn good.

They all looked good with the typical brown looking deposits around the tip. Plug #10 did seem to have a little charred oil deposit around the bottom of the threads, but nothing I thought was a problem.

CPaulsen, you are correct. I found patience to be the best companion. I had set aside the entire day and started early so I would not be rushed.

I was somewhat apprehensive about the job since I had never done a spark plug change on a COP type engine before. However taking the time to be sure I had the right tools, making sure the plug holes were clean and working the new COP boots with finesse made the job less stressful.

Tom

 

Very informative post Tom!

 

QUOTE...(Since the factory manual says the plugs should be changed with the engine warm (not cold or hot) or you could damage the threads in the head, I ran the truck until the thermostat opened then turned it off. The factory manual says "warm to the touch" so "I" took that to mean I should be able to lay my hand on the head casting without it burning so much I had to pull my hand off.)


Hi f250, you reference the factory manual in your original post, what manual is that, Ford or something else? I am thinking about trying this and have watched and read a lot of different things, I'm just trying to gather all the info I can, thanks for your post and help.

 

Hi PA.GRIZZLY,

Thanks for the question, and to clarify, I subscribe to both the Mitchel1DIY and the AllDataDIY shop manuals. Both say they get their online data directly from the genuine Ford shop manuals.

I know you can buy the Ford shop manuals directly from Helm either in print or on CD. However, they are quite expensive up front if you get all the necessary ones including the wiring. I have some old Helm catalogs from the 80s-90s before this new online stuff came about.

The online subscriptions are quite reasonable and both give you the option to print out anything you need, so taking a printed copy of a procedure out to the truck if you need it is no problem. I find that handy when I am chasing some wiring thing.

I did notice you have a 2005 v10, so you will have the two piece spark plugs, not the ones I have in mine.

Be aware of the possible issues when changing your plugs. You can find information on the forum where others have changed this two piece plug. There is a possibility it can separate when removing it, requiring a special tool(s) to extract the piece that remains in the head. I would already have the tool(s) available before you start. I do not know the cost, but you should be able to find the information easily.

There are replacement plugs for yours that are one piece, so I would definitely get those.

Even with the possibility that you will have an issue with the two piece plugs, I would still do the job myself if I were you. You can save a lot of money and you will know the job is done right. That fact alone makes it worth my effort when I can do the job.

Good luck and do research on changing those two piece plugs. Give yourself a whole day for the job. As said before, patience is your friend.

Tom

 

Thanks 250, yea I have the 2 piece plugs and I have seen and read all the horror stories so I guess I need to just buck up and buy what I need and give it a shot, thanks for taking the time to answer my question.

 

Thanks for the detailed write up and pictures. Saved to my F-250 folder for future reference.

 

Excellent write up. Thanks for the info!