Interesting deposit formation on spark plugs

[BobsArmory]

Decided to change out the sparkplugs on my Wife's 2016 Malibu 1.5 liter engine since it was way overdue.
110,000 miles on the original plugs. Supposed to change at 60,000 miles. that's on me.
Old ACDELCO 41-123 New Plugs are ACDELCO 41-156. Don't know why they changed the part number but that's what the parts stores say is OEM now.
Anyway, interesting disk shaped deposits. Never seen anything quite like it before.

 

[otis24]

Are you sure that is a deposit and not just the ceramic insulator? The new plugs might not be identical to the old. Those “domes “ seem pretty uniform.

 

[otis24]

If it truly is a deposit, I would be curious to know as well.

 

[97prizm]

Decided to change out the sparkplugs on my Wife's 2016 Malibu 1.5 liter engine since it was way overdue.
110,000 miles on the original plugs. Supposed to change at 60,000 miles. that's on me.
Old ACDELCO 41-123 New Plugs are ACDELCO 41-156. Don't know why they changed the part number but that's what the parts stores say is OEM now.
Anyway, interesting disk shaped deposits. Never seen anything quite like it before.
View attachment 195433

View attachment 195435

View attachment 195436

The new plugs look more like iridium tips as to me they look slightly thinner than the original electrodes.

 

[otis24]

Could this have been too hot of a plug and melted the ceramic?

 

[14Accent]

That's definitely melted ceramic. You can see how it peeled away from the electrode. What caused it is the question...

That almost seems like too hot a plug.

 

[Jimmy_Russells]

It's just a different design

 

[14Accent]

My fault! Shows what I know when I'm on my phone vs. doing actual research.

I don't believe I've replaced plugs on a newer 1.5T. Interesting design.

 

[BobsArmory]

I didn't think ceramic melted.

 

[jtay2024]

Could this have been too hot of a plug and melted the ceramic?

Ceramics melt at extremely high temperatures. (2000c or so). If the ceramic had melted I doubt there would be an electrode left at all. It does look an odd shape compared to most plugs I've seen before.


OP - Have you been running any additives in the fuel etc? Some octane boosters etc can have metalic particles such as ferrocine (can't spell) or other types that may leave deposits like this.

 

[jtay2024]

It almost looks like welding spatter particles have built up. Perhaps running the spark plug for so long finally burnt through the irridium and caused the base metal to arc and spatter a little onto the ceramic shield.

*Edit* - Just seen the photo of the design difference on the ceramic shape above. It looks like that's just erroded, probably due to length of time in the vehicle.

 

[BobsArmory]

I try to use Gumout all in one every other oil change

 

[BobsArmory]

Looks like Jimmy solved the mystery.

 

[Soft Cars]

I think it's from too much detergent in the gasoline.