Recently changed the spark pplugs on my '09 GS350 AWD. Was a little overdue at 68,000 miles. While swapping out the plugs I took a glance down the shaft and noticed what looked to be significant dark brown deposits where the spark plug leads would sit. I'm thinking of running an additive or cleaner to see if I can flush some of this out. I also noticed what looked to be reside or burn marks on the outside of some of the spark plug tunes when I removed them to get at the plugs.

Has anyone experienced this buildup? Can anyone recommend a Sea Foam treament, or other tratment? I'm a little nervous anout using these on a DI engine. Any help is appreciated.

Thanks

 

Those are quite normal. Just make sure there's no oil covering the threads of your spark plugs - which can indicate a leak at the valve cover gasket.

 

I did notice some oil on the threads of the spark plug on the passenger side nearest to the firewall. Should I look around for a leak? Does anyone know if this is covered under the powertrain warranty?

 

yea leave it and take it to the dealer. thats not a good sign if you have oil on any of the plugs. best to get it in now. I would think that is covered under your power-train but call another dealer and ask.

 

Always assumed the spark plug change was due at 100k. Good thing you did yours early.

 

Well, it was only a few drops present on the threads. I spoke with the local Lexus dealership; they won't touch it because they said the oil present was within normal range. They said they'd only change the valve cover gasket if there was evidence ofa significant leak or if the tube were flooded.
I spoke to my mechanic (independent shop, very reputable) who said that it should not be a problem. If after 68k mile only 1-2 drops of oil were present on one plug, it's not a great concern. So I guess I'll jut have to monitor it for signs of leakage. The bummer is that the powertrain warranty runs out in 1500 miles, so here on in, I'm on my own.

Should I be worried? Or is this one of those "just keep an eye on it" situations? I was planning on doing a seafoam cleaning on the fuel, crankcase and through the vacuum hose, but now I dont know. Thoughts?