Jim Grant's Tech Tips
Ford Explorer, Blown Out Spark Plug
had the number one spark plug on my ‘00 Ford Explorer blow
out. The electrode blew right out of its socket. I had to
tap out the remainder of the plug and I apparently did not
get it all. When I restarted the engine it made one hell
of a racket and would barely idle. I removed the cylinder
head and found no damage to the valves but the piston has
a piece of metal about 1/4 of an inch in diameter lodged
in it and the cylinder head is pretty nicked up. The cylinder
walls are not damaged. I can grind this metal off the top
of this piston and do a valve job, lifters timing chain
ect. Can I expect it to run properly? My concern is damage
to the piston, rod and or bearing. Any advice would be greatly
say thats an $800 to $1000 question on a good day.
A ¼” piece of wreckage hammered into the top of the piston
can cause untold or is that unseen damage. My recommendation?
Pull the motor and replace the damaged piston. Have the
connecting rod checked, replace the bearings in that cylinder
and be sure to have the head inspected for possible cracks.
Your situation is why many shops will have nothing to do
with a broken spark plugs of any kind. Its hard for
the customer to understand all the possible expenses that
may or may not occur from what is often perceived as a simple