So I've read on the subject and have talked to many on the blow out problem with these motors and had the misfortune of this on mine about 5k miles ago at around 104k in my wife's Expedition. Well when it blew out breaking the coil out with it she want close to home so I roadside fixed with another coil I had and another plug that actually threaded back in. It lasted about 3wks and blew out again. So at that point I had a shop throw an insert in. I didn't have time or tool kit and it needed to be up and running quick. My problem is that the plug just blew out again. This is the third plug back on the drivers side which everyone seems to have the most trouble with. The shop is taking a look at it on Monday but I've never seen a plug blow out of a steel insert. The threads on the plug are perfect but the tip is bent over the electrode completely. I'm actually wondering if the piston is hitting the plug and pushing it out. The plug only lasted a month in a steel insert. Has anybody heard of a piston pushing the plug out? The motor runs and sounds fine until the plug is out. Wondering if a pin is worn or something is stretched. Sucks because it just hit 109k as it blew. Thanks for any input

 

IMHO, if the piston hit the plug hard enough to push it out, the piston would have damage as well.

 

+1 there!

I'd have your shop run an inspection camera down the plug hole and look around---that might help diagnose all this.

Odd that its just one plug affected though, especially the bit where no thread damage seems to occur.

I'd be highly interested to know more about this, never yet heard of it here.


Hope its not too severe a repair though!

 

MY bet is you are looking at a new head, after my insert blew they said it was very rare you could get another one in. Either new head or replacement engine, with your low miles a new head might not be bad.

 

If the piston is close enough to hit the spark plug, it would have done it as soon as the engine was cranked right after the repair.

My guess is something was wrong with the insert or its installation. The plug has a crush washer that needs to be seated against the aluminum head itself. If the insert is too large, the plug washer will be seated against the insert not the head itself.

Andy

 

If they used a "timesert" brand insert, they probably did not use the last tool to finish the job. Have them redo it. Timesert is the only way to go aside from a new head.

If they use a different brand, scrap the head. It is done for. Helicoils simply will not work.

On a side note, what year did ford revise the head.