2.0 Spark plugs, #4 - corrosion

[Doubleaaron]

Just changed my spark plugs preemptively at 46000

found corrosion on number4

last year, dealer had my Jeep for 6 weeks to replace a leaky oil separator.

suspect they might have had it sitting outside opened up for a while. Was in Jan/feb

thoughts?

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[Old Jeeper]

Just changed my spark plugs preemptively at 46000

found corrosion on number4

last year, dealer had my Jeep for 6 weeks to replace a leaky oil separator.

suspect they might have had it sitting outside opened up for a while. Was in Jan/feb

thoughts?

Seen that many times before, looks like blow by burnt oil and leaked around the washer.

 

[limeade]

To me, it doesn't look like blow by from burnt oil. It appears whatever caused the rust/discoloration came from the top and was stopped by the washer. The electrode and threads to #4 look same/similar to the other 3. The threads to #4 would show blow by all the way up to the gasket if it was blow by. I would not worry about anything wrong internally.

Some water or other substance has leaked down onto the head and sat in the valley to the #4 spark plug for a while. As long as the coil boot was fine, I wouldn't worry. Pull the plug after 1k miles or so and inspect to see if the problem lingers. I'd use compressed air to blow out the spark plug valley first to ensure there's no loose debris to fall into the cylinder head before pulling the plug.

 

[Rick4570]

Seen that many times before, looks like blow by burnt oil and leaked around the washer.

Thats the worst diagnosis I have ever read on here.

 

[Rick4570]

To me, it doesn't look like blow by from burnt oil. It appears whatever caused the rust/discoloration came from the top and was stopped by the washer. The electrode and threads to #4 look same/similar to the other 3. The threads to #4 would show blow by all the way up to the gasket if it was blow by. I would not worry about anything wrong internally.

Some water or other substance has leaked down onto the head and sat in the valley to the #4 spark plug for a while. As long as the coil boot was fine, I wouldn't worry. Pull the plug after 1k miles or so and inspect to see if the problem lingers. I'd use compressed air to blow out the spark plug valley first to ensure there's no loose debris to fall into the cylinder head before pulling the plug.

Exactly right!

 

[Old Jeeper]

To me, it doesn't look like blow by from burnt oil. It appears whatever caused the rust/discoloration came from the top and was stopped by the washer. The electrode and threads to #4 look same/similar to the other 3. The threads to #4 would show blow by all the way up to the gasket if it was blow by. I would not worry about anything wrong internally.

Some water or other substance has leaked down onto the head and sat in the valley to the #4 spark plug for a while. As long as the coil boot was fine, I wouldn't worry. Pull the plug after 1k miles or so and inspect to see if the problem lingers. I'd use compressed air to blow out the spark plug valley first to ensure there's no loose debris to fall into the cylinder head before pulling the plug.

I won't argue the point with you as I don't deny your thought. What caught my attention was the electrode, note it's burnt vs the others. That burn comes from either a way-too-rich fuel stream or blowby from oil.

Several years ago on my Jeep started running very rough and I was traveling at the time so no tools on me. Passing thru a town I dropped my Jeep off and told them about the rough running and slightly blueish smoke.

There was a motel just down from the Jeep place so I figured I would leave my Jeep and walk down to the motel. By the time I walked down to the motel and walked into the guest entrance my fone rang and it was the Jeep place. They told me my Jeep was fixed so I walked back. What they discovered was my 6 cyl the # 5 Sparkplug had come slightly loose and was not firing correctly as a result. They showed me the spark plug that had to be changed as the electrode was burnt and there was some rust and corrosion.

The mech told me this happens from time to time. He said the cause could be water getting down in the plug bay and over time the washer will corrode and cause the spark plug to every so slightly get loose and as soon as that occurs the cyl head pressure will start forcing blowby past the plug aggergating the situation.

 

[CarbonSteel]

With the exception of the rust/corrosion on the hex area of plug #4, the plugs and electrodes all appear to be similar (in as much as you can see in the photos without seeing all angles). I would have no concerns internally.

My concern would be to identify the source of the water/moisture that is collecting on plug #4 and eliminate it.

 

[Ang1Sgt]

Wow! And you are in New Mexico. I could almost understand if it were in New York. And NGK’s normally don’t rust up from what I’ve seen. Of course most of the plugs I’ve changed in the past few years have been pretty well sealed off from the elements.

 

[Old Jeeper]

Thats the worst diagnosis I have ever read on here.

LOL, there is always a Sharpshooter quick to say someone is wrong and. in typical 'I gotcha' fashion' you hope to point it out and be correct.

But you guys NEVER pose an answer, all you want to do is attack and answer, never give one. LOL, I love that!

Just remember a wrong answer is better than a NO answer...and take that from someone who taught at the post-grad level a course in Hierarchical Structured Database Design. I told my students I am not here to test your knowledge but rather to understand YOUR understanding so that I can tailor the course to you.

 

[Doubleaaron]

Wow! And you are in New Mexico. I could almost understand if it were in New York. And NGK’s normally don’t rust up from what I’ve seen. Of course most of the plugs I’ve changed in the past few years have been pretty well sealed off from the elements.

When the dealer replaced the oil separator, there was coolant everywhere, had them clean it a few times, probably from pressure washing the engine compartment

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