Sparkplugs dipped in oil

[02V8Sport]

Since the LS is prone to valve cover leaks and having the oil wells fill up, I figured I would ask this question because I couldnt get a mechanic friend of mine to give me an answer.

My plugs have been soaked in oil for months and I just replaced all the valve cover gaskets today on both sides in 4 hours, pretty easy job.

Before I just used a syringe with a 1/16" brass tube attached to it to suck up the oil in the wells and the car still sputtered/misfired with no codes. This time I changed all 8 plugs and the sputter went away. This leads me to believe the plugs could be damaged internally somehow from the oil. Any thoughts?

 

[SoonerLS]

That seems unlikely; there's not much more than ceramic insulator, iron/steel, and platinum in the plugs, and none of those are damaged by exposure to oil.

It is possible that the plugs were improperly gapped, or that the insulators were cracked, but it's doubtful that the oil had anything to do with their problems.

 

[02V8Sport]

thanks for the reply. Is there a possibility that oil will get into the internals of the plug and cause it to misfire though?

 

[SoonerLS]

thanks for the reply. Is there a possibility that oil will get into the internals of the plug and cause it to misfire though?

If the insulator's cracked, yeah, but if the insulator's cracked, all bets are off anyway. There are really only three pieces to a spark plug: center electrode, insulator (normally porcelain/ceramic), and the outside electrode (the correct name escapes me at thew moment). As long as the plug is gapped correctly and the insulator is intact, oil shouldn't bother the plug.

I suppose it is possible for the oil to short-circuit the setup, and cause the spark to travel down the outside of the plug instead of along the center electrode. That would be a misfire, and over time, that could conceivably damage the insulator, allowing misfiring even after the oil is gone.

 

[97stscaddy]

I suppose it is possible for the oil to short-circuit the setup, and cause the spark to travel down the outside of the plug instead of along the center electrode.

Oil doesn't conduct electricity.
I would blame it on just gunked up plugs due to the misfiring. Your coils may be on their way out though, so even with new plugs the misifirng may come back in a few weeks or months down the road.

 

[02V8Sport]

Oil doesn't conduct electricity.
I would blame it on just gunked up plugs due to the misfiring. Your coils may be on their way out though, so even with new plugs the misifirng may come back in a few weeks or months down the road.

I avoided all that. I put in 8 new plugs and 8 new coils along with all new valve cover gaskets on both sides yesterday. Car isnt misfiring at all. I was just curious to know if the plugs could get damaged somehow by being soaked in oil for so long.

 

[MDavis0424]

Oil doesn't conduct electricity.

Motor oil by itself does not conduct electricity, but put it in an engine for 3,000 miles and it will collect enough carbon blow-by from the rings to be slightly conductive. Still, it seems unlikely to me that oil in the plug wells could damage the plugs. If it did, I would think damage to the plugs would be pretty obvious, either cracked insulators or burnt carbon tracks down the outside of the insulator.

 

[Quik LS]

The oil may get into the boot and mess up the connectivity of the coil to the plug.

 

[02V8Sport]

every plug has a dark brown ring burned into the insulator thats why I asked about this issue.

 

[97stscaddy]

Looks like oil stains to me. When the coil is installed the boot reaches almost to the base of the plug, but the very bottom part of the insulator is still exposed to the oil. I dont think oil can soak into ceramic, those are probably just surface stains.

If you're good with a dremel maybe you can cut one of them in half and see if there really is any internal damage.

 

[Jim Henderson]

Probably just some of the spark getting conducted down the insulator away from the spark gap. That is why plugs should be clean and the boots not greasy. High voltage always wants to take the easiest path. Sometimes that path is NOT to the electrodes. It doesn't take much to distract the electrons. That is why insulators have those ridges, it makes the physical length of the path the spark might try to take, longer. Strangely some plugs do not have these ridges, hmm wonder what that means.

There is a dielectric gease sold at stores that helps prevent the spark from getting away down the insulator and it also makes removing the boots easier.

Plugs are pretty fool proof as long as they don't have cracks or deposits.

Good Luck,

Jim Henderson