Blown spark plug - 1997 Ford Crown Victoria

Demise, Buy the whole Ford spark plug rethread kit, no guessing involved. You can google search for the kit, to get a good price.
Check the attached links,instruction and guides, Good luck
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Actually, rather than replace the head, you can fix the spark plug hole with a "Time-Sert":

http://www.timesert.com/

One thing they talk about on the site, "Ford spark plug blow-out? Repair kit part number 5553 Ford Triton spark plug kit will repair blown out spark plug's in Ford heads."
Here's the page for Ford's repair kits:

http://www.timesert.com/html/sparkplugford.html

I've used these for years, and they work great!
Much better than a Helicoil, as the Time-Sert retains full thread strength!

But....I would STILL recommend removing the head to do this repair, so as to avoid metal chips/shavings from falling into the cylinder, but you'll save the cost of a new head!

you either have the wrong spark plugs or your spark plugs are blown. go to autozone and ask them what type of spark plugs your car needs. or go to a mechanic and get it fixed

Do a combustion leak test at coolant filler cap,
for exhaust gasses

Clean up coolant in plug wells & pressure test
cold & hot

Do you push them on until you hear or feel the "click", meaning the wire's metal end has engaged the top of spark plug? Look at the top of the spark plugs. Is the little metal end of the plug still screwed down tight?
Wires don't get blown off, ever. You may need to check if the plug wire ends are correctly fitted to ride over the end of the plug and snap tight onto the spark plug. Good luck.

getting oil on top side of motor could be head gasket bad.

Oh, ok. No, they shouldn't be related. The plug cover meaning the spark plug wire boot that goes over the spark plug hole? Why won't it stay in? Is the spark plug missing? Those plug wires snap onto the spaek plug holding the wire on the plug.. There should be a spark plug in the hole. If not, you probably had it blown out. That happens once in a blue moon. If the plug is missing, get a new one and carefully install it by hand, no rachet. If the plug won't start in the hole the first few threads mat be strippe. Do not cross-thread the new plug. Spark plug hole taps are available at parts stores. good luck

Possible blown head gasket...sounds like it, remove the spark plugs and do a compression test, sometimes you will find water coming out of the spark plug hole with a blown head gasket, pull the plugs and turn the engine over, with the radiator full of water, if water starts spitting out of any of the spark plug holes...it's a cracked head, or blown head gasket.

hey, mad legend, have u checked for spark and gas yet? If not, that's the 1st thing to do. To check for spark, u can use a spark plug u took out recently when u changed the plugs. Disconnect a plug wire at plug, plug into used plug, place where u can see tip of plug easily, have someone crank engine over, u should see a good spark at plug tip. To check to see if it's getting fuel, attempt to start several times, pull a plug and check it, tip should show signs of fuel. If it's dry, no sign of fuel, u may have a fuel pump issue.