Spark plug dropped

CASMIHOK

MEMBER
2005 JEEP LIBERTY
3.7L
6 CYL
4WD
AUTOMATIC
160,000 MILES

This is just a paranoia question more so, but my buddy dropped my one of my new spark plugs on concrete about two and half feet above the ground. I didn't want to make him feel bad I quickly inspected everything looked okay to me, but just wondering how durable these things are? I saw no cracks or visible damage. Is it likely functioning 100%? Thank you in advance and hope you're having a great night.

Wednesday, November 6th, 2019 AT 4:19 PM

4 Replies

KASEKENNY

MECHANIC
18,907 POSTS

As long as you don't see any cracking in the porcelain then you should be good. Clearly if the tip or electrode is pressed in then that can just be bent back to give the proper gap so the only thing you have tow worry about is the porcelain.

I would just keep an eye on how it runs. If you have a crack in the porcelain then it will arc through the crank to the engine block and it will misfire. You can also start the engine at night and lift the hood and inspect the plug to see if you are having any arcing. I just can't remember if the 3.7L allows you visibility to see this or not.

However, if it is not misfiring then you are good. If it is not going to sit well with you, just replace it again to be sure. One plug is only a couple bucks.

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Wednesday, November 6th, 2019 AT 5:12 PM

CASMIHOK

MEMBER
204 POSTS

Thank you! The 3.7 actually you have to take out the ignition coil, so no visibility. I inspected it and so did he, I didn't notice anything wrong with it and he didn't say anything. I think it will be okay, can't help but worry though. Thank you! Once I get other things fixed, I'll check to make sure it is working out okay. :)

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Wednesday, November 6th, 2019 AT 5:16 PM

KASEKENNY

MECHANIC
18,907 POSTS

Sounds great. I am sure you will be fine as well. Cracks are pretty obvious. Thanks for the update.

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Wednesday, November 6th, 2019 AT 5:19 PM

CJ MEDEVAC

MECHANIC
11,005 POSTS

From what you have described I'd guess the majority of the plug is probably just fine.

The only part that may have been exposed to damage from a low fall would be the ground strap or even the electrode (or even the ceramic around the electrode).

Comparison with another plug and checking the gap with a feeler gauge might rule your plug back in as a perfectly good serviceable part.

In doubt at all?

One new spark plug's cost surely won't exceed $999.99, they probably are still making them.

They still have 'em for my 1946!

Let us know how it goes!

The Medic

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