There is a rumor? going around about the spark plug/boot and ignition blowing out of the cylinder on the 2003 F250 Super Duty 5.4L. I have almost 100k on the engine, but changed the plugs to Bosch made in Germany plugs. I did notice that the threads were longer than the Autolite than came from the mfr. I have had no problem. Is there a problem with this happening?

 

Yes it can happen, all the ford plugs now have the 8 threads, the '03+ 2V heads have 8 threads too but they can still spit. It is not a plug issue.

 

If you know it is not a plug issue, then what is it?

 

The problem is the small amount of threads on the 2v heads spark plug hole. The 3v heads don't have that problem. Good thing you changed to the full thread plugs but still use a small amount of antiseize on the threads. So you don't strip them out next time removing them.

 

The issue of blown plugs tends to be more related to the head and not necessarily the plug itself. Our Modular motors do not like any brand other than Motor Craft or Autolite equivalent version. Believing more threads will reduce or eliminate this doesn't hold water.

It would seem many, many blown plugs are the direct result of plug hole damage created when they are installed. While it's 100% possible this can be a spontaneous thing most often its a heavy handed mechanic cross threading or over tightening the plugs.

I've always used Motor Craft, a dab of nickel-based anti-seize on the threads and slowly pull them up to 21-23 ft/lbs, stopping once the torque wrench clicks. So far I've been trouble free.

 

Thanks. But they are lifetime plugs and don't plan on changing them again. Pain in the ***/back! Use Lucas Gas Conditoner and lot of highway driving. Maybe they will last 100k+?

 

Maybe they will start misfiring at any time.