[Fox213506]

So yesterday i was getting ready to leave the house turn my car on and forgot to lock the house. I get a few steps away from the car and i hear a boom. I kinda knew it was a spark plug blowing out. so i run back to shut the engine off. from there i decided to cancel my plans for the day and see what the problem was. I unbolt the cover on the oil packs and the first thing i see is a long spring on top of a coil pack. i can already tell which spark plug blew out. pull the coil pack out then the spark plug along with the threads attached but the worst of it all is that the spark plug is missing the electrode and the metal piece on top, everyone can guess were those pieces are. It does make sense about the pieces because i did here some pinging before i shut the engine off. i understand the what to do about the threads in the spark plug hole, but how do i get the pieces out of the engine? or since i heard the pinging its already too late and now im looking at a rebuild?

The plug that blew out was the drivers side all the way to the back, #8? Car is a 1999 Cobra 114500 miles

[DickH]

Maybe not a bad time to throw new heads on the car? It might be pretty hard to get tiny pieces of the plug out of the cylinder and if it ran with those pieces you can bet your combustion chamber is probably scarred from them. Also if you try to repair your threads with the head on the car you risk getting even more pieces of metal in your cylinder. Of course you can always clean everything out but you really dont know the extent of the damage until you get a good look at it.

[Cabikejumper]

My plug blew out in my GT minutes after taking ownership.

I bought a repair kit, plug, and the spring/boot deal all for 65.00

Used a shop vac and slid a wet rag down attached to a metal rod to get the shaves out.

After ~4000 miles it's held up, forgot to use locktite too.

[Fox213506]

Yes, i have been given it a couple days and i finally went to take a second look, and i think it worse than just sticking a time sert in and calling it a day, I looked again and there is quite a bit of oil in and around the cylinder. Doesn't that mean i got damage on the cylinder walls from the pieces that fell in. It still ran fine when i shut it off except for the fact that it was only on 7 cylinders. Tomorrow it going into the shop since all i can do is assume at this point. Anyway If the walls are damaged what should i do?

[rthouck]

If the walls are damaged you'll need to get it bored.......

[Fox213506]

So got it back today no damage on the walls. Got the keys turned it on felt great almost better than before. I drove it carefully home. I got it home and let it ldle as soon as i open the door i here a definite knock coming from the top of the engine, right around cylinder number 8 (The cylinder i just fixed). It goes away with acceleration. What is it. was not there when i started the car. looked around but didn't find a consistent answer. Back to the shop?

[cschoening09]

might check your oil just in case . other than that if it was me i would run it. if it gets worse take it back and have them check it out.

[Fox213506]

So it gets worse, i think i can here it alot better laying underneath the car right behind the drivers front wheels i can also hear it pretty good all the way at the back of the car. Listening under the hood it sounds like its coming from somewhere in the heart of the engine, cant really pinpoint it. It goes away at about 1200 RPM, it is there under load too. This car is starting to scare me big time. Example: I got a $3500 estimate just to change one head on this car. Cant imagine replacing the whole engine.

[00MustangGtPremium]

Originally Posted by Fox213506 So it gets worse, i think i can here it alot better laying underneath the car right behind the drivers front wheels i can also hear it pretty good all the way at the back of the car. Listening under the hood it sounds like its coming from somewhere in the heart of the engine, cant really pinpoint it. It goes away at about 1200 RPM, it is there under load too. This car is starting to scare me big time. Example: I got a $3500 estimate just to change one head on this car. Cant imagine replacing the whole engine.

Ive had a rod knock before so hopefully its not that. Id take it back to the shop. Also you could drop the oil pan to see if theres any pieces of metal.

[Fox213506]

Think i just dodged a big bullet, seems that the knock is coming from the A/C compressor. When i turn the A/C on the knock completely goes away. Gonna search on how to fix that.