Spark Plug/Boot Question

[sambishop]

Started my timing belt yesterday and when I took the plugs and boots out (also changing plugs) I noticed that cylinders 3,4,6 had a discoloration on the plugs. In the close up pictures you can see that the actual spark plugs all the look the same though. Is this cause for concern?

 

[Blacklabs]

Might be leaking some oil around the valve cover gasket at the plugs.

Hopefully you have the gasket for coil pack 7 as it is missing in the picture.

 

[sambishop]

yea I have it, it's just not pictured. Does it call for immediate attention? It's not leaking around the outside of the covers

 

[blackoutt]

Since you're installing new plugs just make sure to not touch the ceramics on the new ones, or wipe with alcohol if you do on accident. Torque new plugs to spec. Inspect coil to valve cover seals for any damage or deformation, and clean really well around sealing areas. You shouldn't have any issues other than cosmetic caused by this seal leak and can prevent it from happening again while you're in there.

 

[ben550]

I found mine to be the same when I changed them. The previous owner had them changed. Two were discolored like that. The two that were discolored were very loose. I replaced the plugs and one of the boots. The heat from the loose plug caused the fouling and actually cracked the rubber in the boot...

After everything was changed out and torqued correctly it runs great. No issues.

 

[jow]

Is touching ceramics/porcelain on 07 4runner spark plugs a “known problem” (or good practice) while changing them with bare clean hands vs clean gloves? Thanks for the reminder and info.

 

[blackoutt]

Good practice when touching any spark plug, not model specific. Not required either, I didn't do it for years but do now because I preach it through our service manuals at work. It's a good habit to get into.

 

[Sungod]

They all looked pretty good to me. I wouldn't be concerned at all.

 

[BlackWorksInc]

Probably nothing to worry about. Combination of light oil mist and or blowby seeping through the plug or gasket, makes sense you'd see it on the central cylinders a they'll be more likely to heat soak and start to leak later in life.

Clean the boots very well and try to blow out the tubes with some carb cleaner if you can (don't use too much and flood the cylinders)