Engine and blown plugs?

Tiny
MYSTROSE
  • MEMBER
  • 2000 DODGE NEON
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 215,000 MILES
My husband's car blew out two plugs a couple weeks ago. He replaced them with all new plugs and wires, and it's been fine until today when a plug blew out again. This time there was heavy dark smoke coming out of tailpipe and there was oil all over the engine compartment. Is this an indication of major engine damage?
Wednesday, August 31st, 2022 AT 4:44 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

By chance, can you tell me where the oil came from? It shouldn't have come from the spark plug hole, but it could have.

Also, if the spark plugs blew out, the threads either on the spark plug or cylinder head are likely damaged unless the plug was not properly tightened. Have you verified which one it is?

As far as the smoke from the exhaust, dark smoke usually indicates an issue with the engine getting too much fuel. If it was dark blue, that would be oil. Were you able to verify the color?

Sorry for so many questions. I'm trying to narrow things down. Also, let me know if the engine was running properly prior to this happening.

Take care,

Joe
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Wednesday, August 31st, 2022 AT 7:38 PM
Tiny
MYSTROSE
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The smoke was dark blue, obviously oil burning. The car had been running pretty good prior to this except for 2 of the plugs blowing out a couple weeks ago. When my husband installed the new plugs, he noticed oil on each of the plugs. The oil that is now on the engine had to have come from the plug hole, as it wasn't leaking before this. Could it be that the rings in that cylinder have failed, and the excessive pressure blew out the plug? Also, when the plug blew out a couple weeks ago, could that have somehow damaged the threads?
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Thursday, September 1st, 2022 AT 6:39 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Certainly, if the plug blew out, it would damage the threads either on the plug or the cylinder head. As far as the oil and building pressure, if the rings were bad, it would do the opposite. Compression would lessen.

If the threads are still good in the cylinder head, we need to check engine compression to see if something is failing internally. Here is a link that explains how to do it. You will need a compression gauge, but most parts stores will lend one to you.

Follow the directions in this link:

https://www.2carpros.com/articles/how-to-test-engine-compression

Let me know if you can get that done and the results.

Joe
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Thursday, September 1st, 2022 AT 7:32 PM
Tiny
MYSTROSE
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This morning my husband put the spark plug back in, using some anti-sieze. There's really no way to look to see if there's a problem with the threads. We're going to see if this works for now. Thanks.
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Friday, September 2nd, 2022 AT 7:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

If he was able to install them and tighten them, then the threads must be okay. Hopefully, they came loose which resulted in the problem.

The Loctite is a good idea. Let me know how things turn out for you. I'm really interested in knowing.

Take care,

Joe
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Friday, September 2nd, 2022 AT 8:32 PM

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