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98 dodge stratus spark plug blown out of head

I had the oil changed 2/27/11 drove it home parked it for the night next morning I went out to start it I heard loud clunk. I opened the hood and found a spark plug laying on the head seperate from the spark plug wire. What would make this happen? I have not had the sparks plug changed recently.190,000+ miles.

Did you have the oil changed at a “quick change” place? If so, I would check the oil level. Anything can happen if the engine is overfilled with oil.

It sounds like a coincidence. But now you need to check to be sure that the threads in the holes are not damaged and helicoil the sparkplug hole if necessary. One of them may have been overtorqued when installed and the threads just sitting waiting for an opportune time to fail.

While an overfill of oil can cause sudden loss of oil pressure and subsequent failure of the crankshaft and connecting rod bearings, it cannot cause a spark plug to get popped out. There’s nothing about an oil change that can cause this.

Some/many things can happen due to an over-filled crankcase, but not just anything, like a spark plug popping out.

Going to have to agree…My guess is that it was loose for a very long time and worked its way back out and finally couldnt handle the pressure…literally. I cant count how many spark plug jobs I have done where I removed 1/2 of the plugs BY HAND…no wratchet needed…I dont know who is doing this but it happens A LOT. Now you have to check the viability of the spark plug threads in the head. Hope yours are OK…IF NOT…we need to sell you an ENTIRELY NEW ENGINE…

Sorry inside joke…if the plug hole is stripped…it can be repaired. Let us know how you make out.

My vote is for coincidence and the cause is someone overtightening the spark plugs in the past.
Even oil-induced hydrolock would not blow a plug out unless the threads were already weakened. If that were the case the plug and bottom of the hood should be covered in oil.

So far my car guy said yes threads damaged and we did talk about the last time I had the plugs changed something was not quite right (I can’t remember who I had change them) and that the plug has been slowly stripping it’s way out. Pray for better weather so we can get to the coil thing you guys and my car guy has in hand to put on. Thank you all and I will keep you all posted.

Not to worry. This is not a major repair. Since there’s apparently been an overtightening incident in the past it’s always possible that another could pop out as ham fisted often applies to more than one cylinder.

It might not be a bad idea while repairing this to pop the other plugs out and if nothing else reinsert them and try to determine if any threads seem weak while snugging them back up.
I never, ever use a torque wrench or even a short ratchet while installing plugs. The best method on aluminum heads is to use a stubby ratchet and palm the ratchet head so to speak. Snug is good enough.

Sounds like a coincindence. Spark plug was probably gradually working its way loose for some time. Is the plug wire boot black and sooty? If so, this confirms the plug was loose for some time. If this is a 4 cylinder, it should be a fairly easy repair if your car guy is knowledgeable in repairing stripped spark plug holes. I’ve done several of these on the 4 cylinder engines.

And remember, never use anti-seize of any kind on a spark plug. I won’t allow it in my shop. It creates more problems than it claims to solve.

Oh oh. Debate coming.

Way back when I was about 13 the old man pulled up in the driveway ending his drive home from work. I mentioned to him that the car sounded odd (62,T-Bird,beautiful car) he told me to check it out. Dad was very pleased when I reported it was a sparkplug that came out and I was able to simply screw it back in. There were no quickie lubes back then so it was left unexplained.