Oil on spark plugs

[BrianDye]

4.0 SOHC (2006)

Finally got the daunting task of changing my plugs done today. Went very easy, I was nervous as hell going in to it, but did very well.

All the plugs looked like "normal" used plugs, they had 83k on them. The front drivers side plug (closest to the front of the vehicle) had a very very small amount of oil on it, and I believe the passenger side front did as well. It was just enough to get my attention, not dripping or anything.

Nothing prompted me to change the plugs aside from just reading on here about 80k being the normal time they start to go bad or need replacing, so I wanted to do it. Truck runs fine, as it did before the change. Only difference ive noticed now is just a little smoother start up, but then again, that might just be me imagining things.

Is this something I should worry about?

(They were OEM Motorcraft plugs, which were gapped way too high. All the plugs were at .70-.75)

 

[2000StreetRod]

plug gap

As the plugs age with use the electrodes wear widening the gap. That's the main reason a high mileage plug starts to fail. The voltage isn't great enough to bridge the enlarged gap. Some people reuse their old plugs after gapping to specification. I would only consider doing that if new plugs were expensive or if the plugs were very easy to replace.

Was the oil on the spark plug threads or on the part exposed to the combustion chamber? If just on the threads it could be from leaking valve cover gaskets. If internal (burned) it could be from leaking valve stem seals or worn/broken piston oil control rings on the piston.

 

[BrianDye]

It was just on the threads, is that a common issue?

 

[BrianDye]

Sorry if this is a dumb question, this is all foreign to me.

If it is the valve cover gaskets, is it just like running down and seeping into the threads? (The same thing as if you sprayed some penetrating oil before changing them?) Or is it more serious than that?

Valve covers don't seem too bad to remove, then it's what, new gasket, bolt and replace everything, oil change I would assume? And done?

 

[2000StreetRod]

retorque the valve covers

The valve cover gaskets compress with age and dry out (shrink). If they are leaking slightly just re-torqueing the bolts to spec may stop the leak. The value is listed as 89 lb-in for your 2006 that I think has composite covers compared to my 2000 that has metal covers. If you don't have a lb-inch torque wrench then it's about 7.5 lb-ft.

 

[BrianDye]

I'm gonna have to invest in a torque wrench, I've needed one 2 or 3 times now for this X. That'd be great if it was that easy of a fix. Are the bolts easy to get to?

I would assume it's only a slight leak as I don't have any noticeable oil loss according to my dipstick, and there's nothing dripping on the ground, or burning off (if it IS burning off, I can't smell it like I could in past vehicles)

 

[2000StreetRod]

no experience

. . . Are the bolts easy to get to? . . .

Sorry, but I have no hands on experience with the 4th generation so I don't know.

 

[BrianDye]

Gotcha, well I do appreciate the advice, hopefully one day this week I can get this taken care of. Working the next 2 weeks straight doesn't make for much will-power to start wrenching on my little bit of time at home.