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Discussion Starter · #1 · (Edited)
For my car's 120,000th birthday I gave it 8 all new iridium spark plugs and coil packs.
I bought the car with 80,000 miles on it and have no idea how old these were.
Plug #1 (left side front, as you're facing the open engine bay) was all crusty looking, as was its ignition coil body.
(Note the white dusting.) Plug #2, right behind it, was crusty and oily, with some discoloration on the coil body.
Plugs #3 through #8 were all oily. I mean really oily. As in they were each sitting in an oil bath in their little recesses. But they were otherwise clean and not fouled.
(See photo for plugs 1 through 3.)
What do you all make of this? Is any of this normal/expected?
UPDATE:
OK, so I went back through the forum and I the consensus is clearly that the oil is due to leaking valve cover gaskets. Lucky me. At least I'm glad I figured it out before everybody sent me "Duh!" messages.
So now the only remaining mystery (to me, anyway) is why the gasket leaks aren't affecting only two of the plugs. Also, still curious what the white crust/dust is all about.
Oh, and in the meantime, will those new coil packs be ruined by the oil at their bottom ends?
20210606_185011.jpg
 

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Mine were dry when I did plugs a few years back. The gaskets were getting a little tired though because when my pcv valve froze up in the -20f cold snap in ‘19, the weak link was valve cover gaskets. I had so much oil blowing past the gaskets and onto the headers it was visibly smoking when I popped the hood.
 

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Mine did the same thing ages ago. Having that PCV freeze up, or even partially freeze, will start to push those valve cover and spark plug well gaskets out before they even get old. And if they're already old, well...

I dont think the oil will ruin the new coils, but it's not good in the long run to keep them and the plugs in a bath like that. Plus, as Old509 notes, eventually it'll progress into an extremely uncool smoke show on the headers.
 

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I don't know what that white crust is on the 1st plug, but it's unusual that it's the same on all of the threads. They usually have a clean section where they were threaded and then are dirty or gray at the end. All I can think of was that the plug was not tight and combustion passed through the threads. Hopefully, the threads in the head are not stripped.
 

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I don't know what that white crust is on the 1st plug, but it's unusual that it's the same on all of the threads. They usually have a clean section where they were threaded and then are dirty or gray at the end. All I can think of was that the plug was not tight and combustion passed through the threads. Hopefully, the threads in the head are not stripped.
I was wondering that myself.
That corrosion/rust on the plug is concerning. This looks just like what you'd find in an old field that's in the snowy part of the country or right on the coast.
Yeah, and what's up with those threads that have no 'clean' area on them. 'Course the fact that the picture was taken with the plugs laying on the asphalt... maybe the OP doesn't have a work bench?
 

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Discussion Starter · #6 ·
I was wondering that myself.
That corrosion/rust on the plug is concerning. This looks just like what you'd find in an old field that's in the snowy part of the country or right on the coast.
Yeah, and what's up with those threads that have no 'clean' area on them. 'Course the fact that the picture was taken with the plugs laying on the asphalt... maybe the OP doesn't have a work bench?
Nope. That's exactly how they looked coming out of the engine. Could it be anti-seize compound? None of the threads felt stripped coming out or putting the new ones in. Don't recall if my regular mechanic ever did a compression test on any of the cylinders though. But you'd think there'd be a fault code record for that if it were leaking pressure.
Either way, all seems to be running fine with the new plugs and coils. For now...
 

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I've never seen anti-seize on a plug, so I can't say. Perhaps a ton of grime with a little oil caught in the plug well coated them on the way out?
 

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Anti seize on plugs looks a lot like old water pipe thread paste after disassembly. It's visible but it leaves trace amounts of balled up goop in the threads.
 

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I just changed the plugs on my 2002 1.8t and the plugs looked similar. I took them to a not so local mechanic / tuner and he said; the rust at the top is from combustion blow by where the gases are passing through the plug it self. And it happens when the plugs are in too long. He recommends new plugs every 40k to 60k miles and. I changed mine because the car is nearly 20 yrd and still on original factory plugs and 62k miles.
 

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I just changed the plugs on my 2002 1.8t and the plugs looked similar. I took them to a not so local mechanic / tuner and he said; the rust at the top is from combustion blow by where the gases are passing through the plug it self. And it happens when the plugs are in too long. He recommends new plugs every 40k to 60k miles and. I changed mine because the car is nearly 20 yrd and still on original factory plugs and 62k miles.
FYI, the factory recommendation is 40k on these cars.
 

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Discussion Starter · #11 ·
Evidently, the spendy VW shop I've been relying on for years for maintenance and repairs had never checked the plugs before. (In retrospect, I don't know why I assumed they had!) I bought the car with 80k miles on it and it's now 122k. Embarrassing! But all is well now and I won't let that happen again. (If I keep her that long, that is.)
I also just replaced the engine air filter too. Observations on which I will cover in another post...
 
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