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Ford tune-up gone wrong

by Mark Stull, Apr 14, 2015

Ford tune- up gone wrong     


Some tune- ups are easy and some so not. We got a call from a customer at another repair shop. He said he was having some problems with his engine and had some work done but the other shop said they could not complete the job and his 2007 Ford Explorer was still running bad. We told him to come on in and we would investigate his problem.

We noticed the “Service Engine Soon” light was on and we could tell that it was not running smoothly. I saw some new ignition coils on the vehicle and was wondering why the other repair shop could not fix it. I hooked up my Snap On Solus Scanner and plugged into the diagnostic connector under the dash. I could see on the scanner that he had two different cylinders that were not firing.

 I proceeded to remove the ignition coils and spark plugs from the mis- firing cylinders and I found his problem. Both cylinders had the spark plugs broken off inside the cylinder head. Now I see why the other shop could not fix it. This is not really an uncommon problem. From 2004-2008, the Ford 4.6 3v and 5.4 3v motors found in the Ford F150, Expedition, Explorer, Mountaineer, Navigator and Mustang kinda had a design flaw. The spark plug design is like no other. They are very long and the spark plug tips are pressed together. What happens is the engines build up carbon on the steel shell tips and the spark plug tips break off and remain in the cylinder head when the threads are removed. Ford has updated the spark plugs to help prevent this from happening. The spark plus are still a 2 piece design but instead of being pressed together, they are now laser welded together and can withstand three times the sheer force of the old design. Champion spark plug thought they would be smart and make a one piece design. I have not used the champion brand but have been told by others that they still break.

So how do we get the broken spark plugs out of the engine? Well, the cylinder heads could be removed and taken to a machine shop where they could drill them out but that would be very costly and time consuming on this engine. Not something I would want to do! I have purchased a tool that is made specifically for this job. The tool screws into the spark plug hole where it pushes the broken porcelain piece further into the steal shell. Then another tool is threaded into the steel shell and if you are lucky, the broken pieces all come out of the cylinder head. Then, the new design spark plug can be installed back into the engine. Unfortunately, it doesn’t always work that way. I have had a few cases where I had to use a masonry drill bit and drill into the broken porcelain to allow for more room for the removal tool to grab the steel shell. This is a little scary because if the broken piece does not come out, I am no longer a hero in the customer’s eyes, I am the villain and the cylinder head will need to come off at a much greater expense. I did get the 2 broken spark plugs out and proceeded to change the rest of the spark plugs. The customer was warned that more spark plugs may break. Sure enough, 1 more spark plug did break even after a few tricks that I knew were performed.

Can anything be done to avoid breaking the spark plugs while changing them? The spark plugs have a service life of 100,000 miles but don’t wait that long. 60,000 miles would be about as far as I would go before changing them. Also, a good combustion cleaner should be used before trying to remove the spark plugs such as Motor Vac Carbon Cleaning Machine like we have at Auto Lab Troy. It can help break up the carbon around the spark plugs and make them easier to remove. Also warming up the engine and using a 3/8 impact gun to remove the spark plugs can help. It sounds scary but seems to work pretty well. I really don’t recommend trying to replace the spark plugs yourself and this should be left for a professional. You could really get yourself into a jam and make a bad situation worse. This is why the previous shop did not finish the job. The days of doing your own tune up in your drive way is fading away. Call Auto Lab Troy today and make an appointment to get your Ford truck or Mustang tuned up.



Mark Stull

ASE Master Certified Technician