Oil on Spark Plug threads

[NWSKIUrbanRunner]

Needed to follow up on this. I remember seeing this on another thread but when I pulled my Spark plugs over the weekend the threads did have oil on them. Should I be concerned? I don't see any leaks or weird smoke billowing out of my exhaust.

Any suggestions on what that was from or if that is normal?

 

[scottji]

Needed to follow up on this. I remember seeing this on another thread but when I pulled my Spark plugs over the weekend the threads did have oil on them. Should I be concerned? I don't see any leaks or weird smoke billowing out of my exhaust.

Any suggestions on what that was from or if that is normal?

Valve cover gasket is the most likely culprit.

Here's the thread you're looking for:
http://www.toyota-4runner.org/4th-gen-t4rs/100614-changed-spark-plugs-one-covered-wet-oil.html

 

[ClockWork]

HG:

Oily Spark Plug On A 4th Gen and Misfires On Cyl 6... HELP!!!! - Toyota 120 Platforms Forum

 

[NWSKIUrbanRunner]

So just replace the Cylinder Head Cover Gasket (Valve cover)
Looks like the kit is $15 from Rock Auto

 

[scottji]

So just replace the Cylinder Head Cover Gasket (Valve cover)
Looks like the kit is $15 from Rock Auto

Because it's such a cheap and easy fix, that's where I'd start. Get some hylomar or sensor-safe hi-temp RTV to use on any suspect/weak/uneven areas.

Does the kit include the little flange-type discs for the valve cover bolts? If not, pick up some of those.

 

[NWSKIUrbanRunner]

Looks like if i scroll down there is one for 25 bucks. But yes it has the gaskets for the tubes as well and the grometts. As for removing the Valve covers it looks not terribly insane. Just i need to remember and label where everything goes instead of "Ohh hey extra hose i dont need that" haha

If I do this, would everyone like me to take pictures and post them as DIY How To?

 

[scottji]

Looks like if i scroll down there is one for 25 bucks. But yes it has the gaskets for the tubes as well and the grometts. As for removing the Valve covers it looks not terribly insane. Just i need to remember and label where everything goes instead of "Ohh hey extra hose i dont need that" haha

If I do this, would everyone like me to take pictures and post them as DIY How To?

Yes please on the pics. Be sure to get a few pics of the inside of your motor with the VC off so we can all see the benefits of frequent oil changes (assuming it's clean and sludge-free).

You are right, it's probably not too difficult. Be sure to label your coils so they go back in the same order. It's probably fine if they don't but I've heard it's good practice to put them back the way they came out.

I use zip-loc sandwich baggies with labeled masking tape to sort odds and ends when working on the cars. I replaced the valve cover gasket on my BMW when I replaced the seals in the valve timing mechanism (Vanos), so I had all the hardware for the engine cover, the hardware for the valve cover, the hardware connecting the Vanos, and the internal parts/hardware of the Vanos, all off the car. Having a ton of little baggies all labeled with the proper part took a little extra time but was very well worth it.

 

[tmangino7]

Sorry to revive and old thread, I am a new member and cannot post a thread yet.

Just purchased a 2006 V6 sport edition 4runner with 123k on the clock.

I just replaced the plugs today and am a little concerned. There was oil on all 6 of the threads of the plugs.

They look to be original as the left side was Denso's and the right side was NGK's.

Any idea what could be wrong it does not seem normal.

Thanks guys If i can upload photos I will attach below

 

[tmangino7]

pics

 

[AuSeeker]

Sorry to revive and old thread, I am a new member and cannot post a thread yet.

Just purchased a 2006 V6 sport edition 4runner with 123k on the clock.

I just replaced the plugs today and am a little concerned. There was oil on all 6 of the threads of the plugs.

They look to be original as the left side was Denso's and the right side was NGK's.

Any idea what could be wrong it does not seem normal.

Thanks guys If i can upload photos I will attach below

Did you even read this topic?

Your question has been answered within the topic, i.e. the valve cover gaskets more specifically the seals
on the sparkplug tubes, you maybe able to simply tighten the valve cover bolts and it may solve the issue,
my valve cover bolts were loose and needed tightening, but be careful not to over tighten them as they can

break or strip out the threads, they need to be torqued to the proper specs, these and other bolts need to
be checked as preventive maintenence, it states this in the maintenence schedule that came with your T4R.

That all being said I would just replace the valve cover gaskets and tube seals, should all come in the gasket kit,
but be sure to check that it does.

The reason I would replace them is that over the years the gaskets and seals have most likely hardened and
will no longer seal properly.

By the way other than the oil your plugs they look to have normal wear, the insulator is tan as it should be,
the metal electrodes are a bit worn and the gap appears to be excessive, looks to be twice the normal gap,
but still normal concerning the mileage, since on the V6 they should be replaced every 30,000 miles when
using the recommended copper plugs, hince they should have been replaced at least 3 times with that mileage,
4 times including this time.

 

[tmangino7]

Did you even read this topic?

Your question has been answered within the topic, i.e. the valve cover gaskets more specifically the seals
on the sparkplug tubes, you maybe able to simply tighten the valve cover bolts and it may solve the issue,
my valve cover bolts were loose and needed tightening, but be careful not to over tighten them as they can

break or strip out the threads, they need to be torqued to the proper specs, these and other bolts need to
be checked as preventive maintenence, it states this in the maintenence schedule that came with your T4R.

That all being said I would just replace the valve cover gaskets and tube seals, should all come in the gasket kit,
but be sure to check that it does.

The reason I would replace them is that over the years the gaskets and seals have most likely hardened and
will no longer seal properly.

By the way other than the oil your plugs they look to have normal wear, the insulator is tan as it should be,
the metal electrodes are a bit worn and the gap appears to be excessive, looks to be twice the normal gap,
but still normal concerning the mileage, since on the V6 they should be replaced every 30,000 miles when
using the recommended copper plugs, hince they should have been replaced at least 3 times with that mileage,
4 times including this time.

I appreciate the response. I did read the thread and many others.

Given that this was about 7 years ago I wanted to see if anyone may have found a different or better solution (different/better brand etc.) as apposed to replacing a clearly problematic seal with another oem which may cause the same issue etc. Or is this something that may be just do to time/age as apposed to the quality of the seal?

Also I found it troubling that all of the spark plugs had oil on them and what looks to be a consistent amount on each.

Thank you

 

[AuSeeker]

I appreciate the response. I did read the thread and many others.

Given that this was about 7 years ago I wanted to see if anyone may have found a different or better solution (different/better brand etc.) as apposed to replacing a clearly problematic seal with another oem which may cause the same issue etc. Or is this something that may be just do to time/age as apposed to the quality of the seal?

Also I found it troubling that all of the spark plugs had oil on them and what looks to be a consistent amount on each.

Thank you

There is no other solution, the maintenence schedule says to check bolts for a reason, over time and mileage some bolts and nuts can tend to loosen just from vibrations, especially smaller bolts and nuts and I'm guessing since those are the original plugs the bolts on the valve covers have never been checked for being tight, also over time rubber can get hard and not seal as well as it did when new.

Also keep in mind that the oil has had 13 years and 125,000 miles to seep past the tube seals.

If the valve cover bolts are loose and or the tube seals dried out and hard, oil can seep passed the seal and pool up around where the plugs seal to the head and when you removed them the oil coated the threads as they were backed out of the head, you really don't have a big issue here just replace the gaskets and seals and the issue will be solved for many, many miles and years, especially if you check the bolts every 10,000 to 15,000 miles or so.