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When is a plug blown out? (1999 Ford F250)

Ok I have a ? How do you know when or if a plug is (blown out)

Do you mean worn out, not working or blown out of the head? We need some clarification.

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The spark plug will be dangling on the end of the spark plug wire. Or the spark plug wire will be dangling with no spark plug.

And the engine will misfire and make one hell of a racket.


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Unless you’re talking about a freeze plug, in which case the best way to know that it’s blown out is to see the hole where the plug should be…


I’m assuming this is a 1999 Ford F-250 Super Duty with the 5.4 liter 2 valve Triton V8

If so, yes, these engines were well known for blowing out spark plugs

The tell tale give-away is an engine that isn’t running well, the check engine light is on, maybe even flashing, the engine is louder than normal

The proper solution is to install a time-sert. Depending on how bad it is, you might even need to install a “last chance” time-sert

I have a buddy and his family had a 5.4L Expedition. His mom was driving the car and it went BANG like a gunshot and then started to run crappy with a lot of noise. It blew out the plug and I think he had to replace the coil on plug as well.

He installed some type of insert with a narrower diameter plug that was made just for these engines/cylinder heads. Everything seemed fine but his dad had the itch for a new truck after that so it was traded in. Apparently this is/was a stock item at most AutoZone stores at that time. I assume it still is.

I’ve seen off brand inserts blow out on these 2V Triton engines

The time-serts seem to hold up better, at least based on what I’ve seen

There should be no play at all when you push sideways on an installed spark plug. If there’s any movement at all the plug is working its way out of the cylinder head and the cause must be addressed. It may be necessary to remove the coil packs before you can do this, don’t know.

If a spark plug has blown out… you will surely notice, believe me. It wont involve asking anyone anything. If this condition is not present and you are asking this question, then you may be trying to describe a misfire, where one or more spark plugs are not sparking or firing as they say. But if any plug has blown out…I promise, you (and anyone nearby) will know something is awry.