Oily spark plug on 4th Gen @ 65K

[malmgren]

I did a full tune-up today on my 2007 4Runner. When I pulled the plug on the driver side rear (closest to firewall), I noticed that the gasket had some oil on it and the tip was gray-er than the other 5 I pulled out.

Should this be anything to be concerned about? In the pics, I have a closeup of the plug in question and then all 6 plugs for comparison.

2007 v6 4Runner @65K miles. Oil changes within 500mi of service intervals, although this tuneup was a 5K overdue.

The only strangeness it's given me is about a month ago, when it started, the engine was knocking more than usual (almost sounded like it was starved for oil) with some white/oil smoke for a few seconds and then it returned to normal. Every other start since then has been fine.

 

[hearno]

driver side closest to the firewall, isn't that #6? hopefully it's just the tube seal but coupled with the white smoke and "knocking noise" for a moment, might be another issue.

 

[malmgren]

I'm not sure what the firing order is, but yes, closest to the firewall driver side. The group pic was not taken in order.

I was thinking tube seal as well, but the gray tip compared to the other plugs has me concerned as well.

And one thing to mention about the "knocking" event is that this happened only after I had previously started the 4R for about 20 seconds to move it. It was a cold start, so I was thinking maybe oil didn't have time to circulate or hell, I'm not really sure.

I don't think it's worth taking into the dealership for yet, unless this sounds worse than I'm thinking it is.

 

[Bob J]

Could be a blown head gasket..... 1GR-FE engines have a history of this problem with cylinder #6.....

 

[hearno]

I'm not sure what the firing order is, but yes, closest to the firewall driver side. The group pic was not taken in order.

I was thinking tube seal as well, but the gray tip compared to the other plugs has me concerned as well.

And one thing to mention about the "knocking" event is that this happened only after I had previously started the 4R for about 20 seconds to move it. It was a cold start, so I was thinking maybe oil didn't have time to circulate or hell, I'm not really sure.

I don't think it's worth taking into the dealership for yet, unless this sounds worse than I'm thinking it is.

Could be a blown head gasket..... 1GR-FE engines have a history of this problem with cylinder #6.....

That's exactly what I was getting at. OP, you should search head gasket issues. Most present with the problems you've mentioned. A cold rough start that smooths out after 20-30 seconds. It usually fails around the #6 cylinder too. The gasket was redesigned between 05-06, no one is sure when exactly but the 07s and up should be good. Not to say that it's not possible though.