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So I swapped out the plugs on my 07 ls 460L. The passenger side firewall plug came out looking dirty and oily(see pics) the driver side plug has some oil too just not as bad. The plug seals on passenger side has to come out so I replaced those, some were cracked.
My question is do i need to be worried about it? Passenger firewall plug Closer look. What's the build up on the prongs? These plugs had yellow triangle on the top of them. Maybe original plugs?
Last edited by Gaberomero; 04-30-24 at 02:18 PM.
Reason: Misspelling
I'll inspect this further. Any positive results with oil additives? Will fixing require removal of the heads?
the car drives excellent. No power loss or any sign of problem. Could this have been going on for thousands of miles?
Last edited by Gaberomero; 04-30-24 at 10:32 PM.
Reason: Forgot to ad info
The tips look mostly dry. That is a good thing. The valve cover gasket and plug seals have likely hardened which will not seal very well. Replace those and you should be ok. The yellow residue looks like gas byproducts. One plug has oily porcelain. That could be leaking ring or valve stem guide. To say it is excessive depends on how many miles are on the plugs. Are you noticing oil loss at the dip stick?
I found oil on my threads as well when I changed my plugs. I am burning some oil and have found zero leaks. I have been told it is most likely the PCV needing to be replaced. My local Toyota/Lexus independent shop is taking my LS next week while I am away traveling for work to flush/drain all fluids on the car and will replace the PCV. They said they will see if the gaskets need replacing but they want to ensure it actually needs it before charging me for such a big task. I appreciate their honesty.
The tips look mostly dry. That is a good thing. The valve cover gasket and plug seals have likely hardened which will not seal very well. Replace those and you should be ok. The yellow residue looks like gas byproducts. One plug has oily porcelain. That could be leaking ring or valve stem guide. To say it is excessive depends on how many miles are on the plugs. Are you noticing oil loss at the dip stick?
Thanks for the useful info. The plug seals are indeed hard. The plugs are original. I have not noticed oil loss or smoke out the pipes in morning at cold start..
I have not got around to replacing the pcv...I believe the last owner was somewhat laxed in the maintenance where the things I've done should have been done already... any tips besides this??
thanks again ..
Last edited by Gaberomero; 05-01-24 at 02:29 PM.
Reason: Forgot to ad info
There are a couple parts that can allow engine oil into the cylinders especially on a car with high mileage (say >100,000 or so). Whether your car develops such issues is a direct result of oil change intervals, an engine with reasonably clean oil takes far longer to create oil burning problems exactly as you'd expect.
In general, oil burning issues are caused by valve guide seal wear, piston ring wear, or sticking piston rings. Worn valve guides/valve guide seals, can allow engine oil into the cylinders as a small amount of oil leaked can be drawn into the cylinder with each intake stroke of the piston. Worn piston rings can let engine oil thrown onto the cylinder bores during normal engine operation, to be pushed past the rings into the cylinder.
Even if the piston rings have little or no wear, they still must retain the ability to compress and apply tension against the cylinder wall during the compression stroke. So it is possible your rings could be like new, but could be "sticking" in their ring grooves on the piston. The piston rings are attempting to do their job of sealing the piston but the rings can't seal because varnish, sludge, or some other crud in the oil has lodged in the piston ring grooves and glued the rings up so they can't compress.
I'd try the easiest solutions first, depending on how much oil consumption, if any, it has, there's probably nothing to lose. I'd try an oil change, maybe even try the next heavier oil like 5w-30 if Lexus recommends it. Plus I think I'd try an additive to unstick the piston rings (I tried something called Star tron ring clean plus deposit control gas additive). Since the only other option is to tear apart the engine and change the valve spring seals + piston rings - the last resort, of course, and in the case of your engine, probably NOT needed all because of oily spark plugs. A little bit of oil on the plugs is certainly no cause for panic, you can probably drive it for years in that condition and never even notice it. So long as the engine performs normally, oil consumption isn't outrageous, and the car will pass smog, you might just continue to drive the car for years unless and until the problem gets worse (which might never even happen).
These engines all have issues with valve cover gaskets and the spark plug tub seals. Spark plug tube seals is the only thing that could be allowing oil to leak onto the top of the spark plugs and then leaking down onto the the threads. Just get a flash light and look down the holes the spark plugs came out of and look for any oil. There shouldnt be any, i am guessing youll find a lot in some of them and a little in the others. Its not a big deal to replace them and the valve cover gaskets at the same time.
These engines all have issues with valve cover gaskets and the spark plug tub seals. Spark plug tube seals is the only thing that could be allowing oil to leak onto the top of the spark plugs and then leaking down onto the the threads. Just get a flash light and look down the holes the spark plugs came out of and look for any oil. There shouldnt be any, i am guessing youll find a lot in some of them and a little in the others. Its not a big deal to replace them and the valve cover gaskets at the same time.
that's next on my to do list. I changed the 02 sensor bank1 sensor 1 a week ago due to p2238 code.
it's driving flawless right now with 0 problems, but tube seals/ valve cover gaskets and pcv is where I'm headed next.
There are a couple parts that can allow engine oil into the cylinders especially on a car with high mileage (say >100,000 or so). Whether your car develops such issues is a direct result of oil change intervals, an engine with reasonably clean oil takes far longer to create oil burning problems exactly as you'd expect.
In general, oil burning issues are caused by valve guide seal wear, piston ring wear, or sticking piston rings. Worn valve guides/valve guide seals, can allow engine oil into the cylinders as a small amount of oil leaked can be drawn into the cylinder with each intake stroke of the piston. Worn piston rings can let engine oil thrown onto the cylinder bores during normal engine operation, to be pushed past the rings into the cylinder.
Even if the piston rings have little or no wear, they still must retain the ability to compress and apply tension against the cylinder wall during the compression stroke. So it is possible your rings could be like new, but could be "sticking" in their ring grooves on the piston. The piston rings are attempting to do their job of sealing the piston but the rings can't seal because varnish, sludge, or some other crud in the oil has lodged in the piston ring grooves and glued the rings up so they can't compress.
I'd try the easiest solutions first, depending on how much oil consumption, if any, it has, there's probably nothing to lose. I'd try an oil change, maybe even try the next heavier oil like 5w-30 if Lexus recommends it. Plus I think I'd try an additive to unstick the piston rings (I tried something called Star tron ring clean plus deposit control gas additive). Since the only other option is to tear apart the engine and change the valve spring seals + piston rings - the last resort, of course, and in the case of your engine, probably NOT needed all because of oily spark plugs. A little bit of oil on the plugs is certainly no cause for panic, you can probably drive it for years in that condition and never even notice it. So long as the engine performs normally, oil consumption isn't outrageous, and the car will pass smog, you might just continue to drive the car for years unless and until the problem gets worse (which might never even happen).
Great info and advice. I'll try some of the Star Tron cleaner since it can't hurt. I'll continue to monitor the oil and it's behavior.
Thanks a ton!
04-30-24, 01:58 PM
Spark plug change getting oil on plugs - problem?
