Coil popped out of head

Question

I've got a 1999 F250-SD XLT 4×4 that the coil just popped out of the head what would cause that? I've not done anything to it yet

Answer 1

Your spark plug was loose

If the spark plug was loose and gone, based upon your comments, the coil did not pop out of your head, the sparkplug popped out of your head.

The last change of the sparkplugs may have been the cause where this particular plug was not properly torqued down in your head. If your threads are stripped in the head, which I doubt, then you have much bigger issues and will need to remove the head to repair the spark plug threads and then re-install.

Properly torque a new spark plug into the head and put the end of wire coil back on it, go for a test drive. I'm sure it will be fine.

Answer 2

Unfortunately I'll bet you've suffered what most every Ford Triton engine owner has. These engines blow plugs quite easily. There was even a class-action suit(s) at one point.

You won't be able to just "rethread". You have 3 options (but really only 1)

1. buy as many different spark plug brands as you can, and carefully torque until you find one that grabs some. Don't overtighten. I've even had some luck in crushing the threads slightly oval in a vice. This is totally shadetree, and only for the folks that can't possibly afford the $400 fix before due at work in the morning. Probably won't last, but gives you some time until #3.

2. Buy the taper thread repair kit and the special very long-nose plug that comes with it. This may or may not last, depending how much original thread is left, but all the ones I have repaired had already attempted this fix and maybe got 2 months to a year.

3. Have it properly rethreaded, and "helicoiled" (thread insert) for the original style and size plug. This is an expensive kit, and not an average DIY job. Check ALL the plugs, and replace them once a year regardless of mileage.

If you want try try #2 or #3 on your own, here's a tip from an oldtimer:

Set the piston to BDC, and fill the cylinder with foamy shaving cream (not gel) until it squirts out the plug hole.

THEN do all your tapping, thread inserting seating, test fit plug, etc.

THEN remove the plug, put a shop vac over the open hole (might have to put a hose reduction on the nozzle, and suck out the shaving foam (and little bits of aluminum) while a helper SLOWLY hand cranks the cylinder back to TDC.

Clean off the plug, away you go. Good luck. Sorry that happened but you are certainly not alone.