Burned spark plug ceramic

Hi everyone,

Yesterday, I changed my Gen 3 transmission fluid and also decided to change my spark plugs as well. I was kinda shocked when I took the plugs out and saw the condition of the spark plugs at 58,000 miles. I understand that these plugs don't have to be changed till 120,000 miles but I just wanted to see how they look.

Burned ceramic means that combustion gasses are leaking out, right? Why would this happen with only 60K on the plugs? Is this why DENSO replaced these plugs (SC20HR11) with the new model (SC16HR11)? I inspected the spark plugs and applied some of that dielectric grease inside the tube (not on the terminals) before putting it back in.

What I also noticed was that the plugs were not dry and had oil on them (all 4). I took some pictures that might help. Please let me know what your thoughts are. It's better to prevent a problem than fixing it in the future

 

Thanks for taking the time and explaining this . It originally concerned me due to the fact that this was the condition at 60K miles, not 120K miles (which is what Toyota is recommending). I've done a lot of Spark plugs change and I wasn't sure about the oil on the threads (the well was oil free and dry).

Again, thanks a lot for everyone that took their time on this post

 

Thanks a lot for comparison, should have done the same

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1st Topic:

It's been 2.5 years since I replaced the plugs and I decided to replace the plugs again at 117,328 miles (60,000 miles on the plugs). The reason was a bit roughness when the ICE engaged after each stop and go. I replaced the plugs with NGK ILKAR7B11 which had better laser welding and ground electrode disc ( I just liked the quality better than DENSO SC20HR11). The ICE engages smoothly and I'm happy. That being said, I have a few pictures and questions,

There are two pictures of the plugs that I pulled out and they look similar to the ones I pulled out two years ago (previous posts). I used a digital endoscope to see what the inside of each cylinder looks like. I would be happy to hear your feedback (sorry about crappy pictures). Cylinder 1 and 4 seemed to look a lot cleaner than 2&3. Does this mean that I'm getting coolant into those cylinders?


2nd Topic:

Also I installed a oil catch can at 60,000K. every 5000 miles I dumped the stuff out (not so much) but I thought the catch can is going to help. I was wrong. I removed the Intake Manifold for clean up and I noticed the same amount of residue inside the cylinder head intake inlet. This time it was so much harder to clean; they were like gum (tar) and it took a long time to clean each inlet. I'm assuming that the catch can had something to do with how sticky the residue was this time compared to last time. I decided to remove the catch can and put back the original PCV valve pipe to the intake manifold.

Now comes the questions,

Can I just disconnect this hose completely so the PCV gases don't circulate back into the engine? Would I get any codes? I was thinking of plugging the inlet on the intake manifold and letting the PCV gas to just vent out.

 

Coolant level hasn't changed and I changed the coolant at 105K. Is there supposed to be a significant change in the level of the fluid?

Yes it's roughly around 60K but I cleaned the throttle body (oil pool) a few times after some oil changes.

As far as the catch can goes, I used the one that NutzAboutBolts used on their video but I filled it up with steel scrubbing pads. Can I just disconnect the hose from PCV to Intake Manifold completely to avoid this?

Thanks

 

I'm actually trying to run an open catch can where the outlet to the Intake manifold is vented out (same as what I previously had set up, but just vent the catch can outlet tube into atmosphere. I live in Nevada now