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Spark Plug Blew Out

Back in May i was in a front end collision. The collision repair said that it was a pre existing condition but the problem didn’t happen until after the accident. There is a miss fire in cylinder 3. Did not fix the problem and told me to drive down the street to another shop, got the spark plug and coil pack replaced and now it blew again. Is this because of the accident? Thank you.

No way to tell and it has been over 3 months. I assume your insurance was used for repair so call them. I think this repair is on you unless this thing is still under warranty.

I’ve never heard of a spark plug blowing out because of an accident.

If a spark plug is cross-threaded or isn’t tightened when replaced it can blow out of the head.

Did they install a thread saver insert before installing the plug?

https://www.amazon.com/Helicoil-5334-14-Thread-Thread-Repair/dp/B0002SRF4O

Tester

When my car told me i needed to replace all the spark plugs for regular maintenance about 8 months before the accident. I went into a shop and they did it. When the damaged happened i had my car towed to the collision center where they just looked at the outside and said my car will drive until my appointment. My hood was crushed towards my dash but it was stuck so they didn’t open the hood bc they wouldn’t have been able to get it down. Then the miss fire after i drove away. they didn’t fix the miss fire and told me to drive three blocks down to Honda where it blew out of where it was.

when i got my car back from Honda it was fine. Less than 1000 miles and the spark plug is melted and coil pack was burnt in cylinder three.
Can all of that craziness be because of the accident?

The coil pack melted because the spark plug was loose before it blew out.

Coil packs can’t handle hot cylinder gases.

Tester

can spark plugs become loose in a front end collision?
sorry im asking a lot of questions

Like I said before.

I’ve never seen it in the almost fifty years I’ve been working on vehicles.

Tester

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Your spark plugs falling out would more likely be the fault of the person who replaced them.

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Concur w/above posters. One idea going forward, usually when a spark plug comes loose it will start to make a noise, maybe a tick tick tick sound at first, and as it comes out further it might sound like a bang bang bang sound. Good idea to idle your car in the driveway once in a while, pop the hood, and get accustomed to the sounds it makes, then you might spot this kind of problem before it damages the coils.

Nevada is correct. The fault lies with the person or persons involved with plug replacement in the past and the collision had nothing to do with this problem.

What should also be considered is that with the threads in one hole being boogered up then there’s a fair chance the others may not be far behind.

You also have an issue with the shop that replaced the plug and coil. It’s their responsibility to consider the “whys” of failures and perform a repair so the “why” will not surface again.

Can you post a photo of the crushed hood?

In general I agree with everything that’s been said, however IF the hood also impacted the top of the coils in a manner to create shock and load to the shaft that carries the spark voltage to the plugs, it is possible (remember, I said possible, not probable) that the impact forced the plug down and damaged its threads. The COP assemblies are like metal posts on top of the plugs, and their tops are right under the plastic shroud under the hood. That would be that black plastic thing running crossways just in front of the firewall.

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can you explain in more detail what you mean by blown again? Do you really mean the plug got blown out of the engine? I don’t see how a collision could have caused that. What year is the car?

The hood crushed right in front of the windshield COULD be a clue to that. Strange things happen in accidents.
See my earlier post.

Sounds to me like the tech who replaced the plugs put all of them in by hand and then went back and tightened them with a tool. But he skipped one. It’s called human error and I never met a tech who didn’t make mistakes.

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