Strange Oil On Spark Plug...Mixed signs...

krunk_muzik

krunk_muzik

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So I decided to check my spark plugs today, after changing them about a year and a half ago, and I was surprised to see what I found (I'll explain later). I was using Bosh Platinum +4 spark plugs (regret using those). The LS runs good, no check engine light, no codes of whatsoever. But when idle, I can feel a light shake/vibration. It's not a very noticeable shake, you can only feel it if you really pay close attention to it. There's also no "blue" smoke coming out of the exhaust that would indicate burning oil. When I go up a hill, the car seems to struggle just a bit to accelerate, sort of like a jerk/shake. So that lead me to check my coils/spark plugs. All coils are good. But when I took my spark plugs out, i found oil on the spark plug threads. Not on the ceramic part, which would indicate a bad valve cover gasket. BUT, there were 2 plugs that had some oil on the ceramic along with rust-like residue on it. So I'm wondering what could cause oil to leak onto the spark plug threads? I posted some pictures so you guys can see what I'm talking about. I'm considering replacing my valve cover gasket...

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Not sure how oil is getting to the threads, but I believe the "rust" appearance is from the plug getting really hot. I could be wrong.
 
krunk_muzik said:
When I go up a hill, the car seems to struggle just a bit to accelerate, sort of like a jerk/shake. So that lead me to check my coils/spark plugs. All coils are good.
Click to expand...

that definitely sounds like it could be a coil or two going out, how did you test your coils to know that they where good?
 
The bottom right plug either was defective (I do have a low opinion of Bosh plugs), or was not screwed in tight enough. The discoloration comes from combustion gases blowing by the outside of the plug.

Oil can leak down into the threads as you take the plug out if the well has oil pooled in it.
 
Silver_LS said:
Not sure how oil is getting to the threads, but I believe the "rust" appearance is from the plug getting really hot. I could be wrong.
Click to expand...

the oil isnt getting on the thread! he's POSTING on the thread the problem is the OIL on the plug!!!! duuuuhhh.......
 
djknowledge said:
the oil isnt getting on the thread! he's POSTING on the thread the problem is the OIL on the plug!!!! duuuuhhh.......
Click to expand...

Sorry, but you're wrong on this one. From the middle of the original post "But when I took my spark plugs out, i found oil on the spark plug threads."
 
1LoudLS said:
that definitely sounds like it could be a coil or two going out, how did you test your coils to know that they where good?
Click to expand...

I had a friend test them for me using a multimeter. He did say one coil pack is going bad, which may be the cause for the jerk/shake going up hill, but that still doesn't explain the oil on the spark plug threads.

oldhead said:
That may be gas on the treads from the plug not firing!
Click to expand...

I've had a few people tell me that. I've also been told that I should perform a leak down test to check for any cylinder leakage which could mean bad piston rings or walls... But there's no oil on electrode that would mean there's oil going in the cylinder. The electrodes are bone dry...:confused:
 
krunk_muzik said:
I had a friend test them for me using a multimeter. ...
Click to expand...

1. They are COPs (Coil On Plug) not coil packs. Coil packs have multiple coils.

2. The typical coil failure on the LS is due to high voltage breakdown. There is no possible way to test for that with a multimeter. You have to do a stress test and use an oscilloscope to monitor the coil. Ford has a TSB out on this. Unless you own the equipment, it is actually cheaper to replace the coils than to test them.
 
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