Oil on Spark Plugs

I changed the spark plugs on my 2010 Tundra today and found oil on some of the plugs. The reference picture shows the plugs in the order they were installed in the engine: plugs 2, 4, 6, and 8 on the left and plugs 1, 3, 5, and 7 on the right. There was a heavy amount of oil on plugs 4 and 6 on the left and plug 5 on the right. The picture also shows that plug 6 had a lot of "gunk" on it. The engine is a 5.7 V8.

Is this normal or an indication of faulty valve guides or piston rings in the combustion chamber? Based on the picture how concerned should I be? The engine was not experiencing any issues with hard starting, misfiring or hesitation. Thanks in advance for any guidance or advice.

 

You could have valve cover gaskets leaks

Did mine at 115k miles

Also did write up.

Not hard. Pack patience

https://www.tundras.com/threads/changing-valve-cover-gaskets.10035/

 

You are correct Haynes manual says worn valve guides or piston rings

 

Oh? I stand down.

I would have thought so since I had same problem and corrected this by changing the VCG's.

 

You are correct. Of course bad valve cover gaskets can leak onto plugs. I was thinking of fouled plugs caused by an internal issue....

 

I didn't have any problem and decided to change mine since I was eBay happy paying $60 for 8 OEM plugs.

After the surgery I was more happy to know one area fixed.

 

How many miles are on your truck?

 

The spark plug tips is what counts. They all look like they have "burned" evenly to me. All of the lower threads look normal as well with the dark black super heated oil stain around each end ring of the plug. What the upper threads and the ceramic ends look like do not matter. Thats not indications of internal engine issues.

They all look like normal wear to me on the end caps and electrodes. That whitish gray color is exactly what you want to see and they all look like they are firing / burning fuel evenly.

If those electrodes and end caps were wet and cover with oil id say that you had a problem with rings or valves. They look to be bone dry. There is some slight black discoloration but nothing at all to worry about in my opinion.

Is the truck smoking?
Using oil?

Those plugs do not look abnormal to me at all.

You have got to be sure to (and hope that you did) apply anti seize to all of the threads on the new plugs before you installed them.

 

Also, remember those plugs sit down in tubes, and those tubes are supposed to be hard sealed to the head and o-ring (kinda) sealed to the rocker cover.
Leaks at the head end seal of the spark plug tube will cause what you see there, because that end is immersed in oil during engine operation.

Steve

 

When I changed my spark plugs out at 130k miles, I noticed the exact same thing for the same plugs that you mention. I researched it and determined that there was an issue on some of the trucks with a smaller gasket component which encircles the spark plug locations. Evidently it is recommended to replace them along with a valve cover gasket replacement. I will likely not mess with it unless it starts making the truck run bad. I have put on an additional 15k miles and two oil changes since I first noticed this. I have had no issues and have not seen any seeping oil out of the bore under the coil pack.

 

See my write up above link.

Replacing the VCa is not hard. Plucking out the tube valves also easy.

Out of 10 being the worse, it's a 5.

 

Thank you everyone for the responses. I "attempted" to change my valve cover gaskets and let's just say that I had to call in the professionals. The best information I found on-line was from Les7311 (which was very detailed and informative) but I couldn't find any YouTube videos or any other resources detailing how to change valve cover gaskets on a 2010 Tundra. That might have been my first clue that this was a big project. The good news is that I diagnosed the problem correctly and the valve covers were in need of replacing. Unfortunately, I found out the hard way I was in over my head when it came to execution. Long story short, I attempted to change the gasket on the driver side and threw in the towel before attempting to change the gasket on the passenger side. I did end up installing the driver side gasket and putting everything back together but I snapped one of the valve cover bolts and created a new set of problems. I ended up taking the truck to my trusted mechanic and he was able to clean up my mess and change the gasket on the passenger side. Fortunately, he is trustworthy and fixed everything for a very reasonable price. His advice was that changing the valve cover gaskets on a 2010 Tundra is not for amateurs (that would be me). He recommended sticking to the smaller V6 engines that have easier access to the valve covers to get more experience before tackling a project the size I was attempting to take on. Again, I don't think it was a coincidence that I couldn't find any detailed videos for DIY'ers like ourselves for this particular project. I think for the time being I'll stick to changing my oil and other preventative maintenance tasks to gain more experience.

On a positive note, we all learn more from our mistakes than we do our successes and this was a great learning experience for me. I certainly wouldn't want to discourage anyone from tackling this sort of project for themselves if they are motivated to do so but, like my mechanic said, this particular project is not for amateurs. Just moving things out of the way to get to the valve covers is a tall task for the inexperienced.

At the end of the day, this was my experience and I was fortunate that I didn't create any significant damage to the engine. I'll keep turning a wrench and getting my hands dirty but I might want to scale back on how much Velocity Channel shows I watch. They make it look too easy! Thank you again to everyone that contributed to this thread.

 

Parker,
You did GREAT by completing one side, and if it wasn't for snapping one of the bolts, you would have hit a home run
CONGRATS!!!!!!!!

There is a thread asking how we all became good at fixing our vehicles....... well your tenacity is prime example, and don't be intimidated. Read up, watch videos, buy a tool, get grease under your nails - ahem, wear gloves.

Glad also you took heed to change the VCG, first sign of oiled spark plugs

Go look over your work, study then VCGs, and hang a PLACRAD over your chest on the beltway saying:

"I WILL CHANGE YOUR VCG FOR HALF RHE COST - TUNDRAS ONLY"!!!!

 

Hi Parker, if you see this, just wondering what it cost you to have the tube seals and VCG’s replaced? That’s where I’m at right now.

 

The tube seals are leaking. The business end of the spark plugs are clean. Tube seals and new valve cover gaskets will fix it. If it were rings or valve seals, the tips would be either brown, black, or coated in an oily carbon crud.

 

Yep, mine appear similar, the guy changing my plugs said $900 to do tube seals and VCG’s! I have another that will do it for $250, just wondering how many hours labor involved. I know I’m unable do it myself.
Thanks!!!

 

Well what did you do?

 

I had a 77 Corolla that had the plugs in the vertical position. The plug wires had a rubber dust cap on them about 4 inches up from the plug that sealed against the valve cover. They would always fail. One time it got so bad that when I removed the plug wire I couldn't see the top of the plug because it was submerged in oil. While it's not a problem it is. What happens is you remove the plug and any oil now runs into the cylinder. If there's only a few drops of oil, no big deal. But if there's enough you can damage your pistons/ connecting rods. Just like water you can't compress oil. In the case of the Corolla I would pull all the plugs, disconnect the power wire from the coil, and crank the engine to blow the oil out of the cylinders. Made for great rustproofing for the underside of the hood but not so great for everything else in the engine bay or my garage floor. Of course back then the gasket materials weren't the same quality as today.

 

So pulled out first plug and this is what I found. Lots of oil. Not sure what this means but don't think it's good. Suggestions?

 

I would suggest changing the VCG. See post #2

 

Thank you. I looked up a "leaking vcg" and I have other signs of the vcg leaking as well.

 

The oil is on the top of the plug, not in the cylinder. The cylinder end looks good. That eliminates anything in the combustion chain, and is a good indication that the rings are good and compression is still what it should be. The spark plug tube in the valve cover has an oil seal at the top. The seals harden and crack over time. When this happens, oil seeps into the tube and coats the exposed part of the top of the spark plug. The clean part at the very top is where the plug is protected by the boot. Pulling the valve covers and replacing the seal will solve the oil problem. You may also need to replace the spark plug boots if they've been damaged by the oil.

 

I was just looking this up!

I'm guessing I need new boots?....or new coils?....

 

It won't matter until you replace the tube seals. The best answer is to look at each plug and boot (the boot will separate from the coil) to see which ones need to be replaced. Once the seals are replaced, replace the damaged boots and plugs to make sure you don't have problems in the future.

 

Randy Morton nailed it! Your plugs look perfect! that oil and crap on the outside is meaningless as far as your engine is concerned.

 

2nd post here- long time Tacoma owner & just picked up a new to me 2010 Platinum Crewmax 5.7L w/ 148k miles. Oil changes were done religiously (Mobil 1), but other fluids were not changed as best i can tell from service records. I had the trans flushed & serviced the front & rear differentials & transfer case all w/ Toyota OEM fluids.

Spark plugs had also ever been changed. Tackled that today & replaced w/ OEM Densos. Noticed oil on 2 plugs: #3 in the pic- driver's side, 3rd farthest from the driver & a very small amount on #6) Other plugs looked ok to my eyeballs, but i'm no expert.

Seems consistent with the valve cover gasket leak that @Les7311 & others have described. How serious is this? do i need to address it? @kenomouth64 How are yours doing without the gasket repair?

Thanks!

 

To me that seems like the VCG and tubs need changing. I did a write up on this and it’s not hard to do.

Thanks and if you have a mechanical inclination than do it.

 

Those look just like what my spark plugs did, when I changed them at 130k. I had oil build up on the top of the plugs. I never messed around with replacing the valve cover gasket or the tube seals. I have not seen any oil coming out of the tube and I have put an additional 45k miles since then.

 

good to know. i'm not going to attempt a DIY fix, but i'm considering letting a trusted shop do it for $340 for peace of mind.

 

That is a great price. I didn't realize it would be that cheap to fix.