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Bull6791

Spark Plug Valleys

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Spark plug valleys are where you stick your spark plug socket in to remove or install spark plugs. They're the round bores on top of your engine's valve cover where you access your spark plugs. The valve cover gasket also seals the spark plug valleys between engine head and valve cover. Oil in the valleys indicate a leak at the valve cover gasket.

 

You can see the 4 larger round holes integrated in the valve cover gasket to seal the spark plug valleys:

 

http://www.rockauto.com/catalog/moreinfo.php?pk=447119&cc=1432915

Edited by dom

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Yeah, at the hexagonal base of spark plug which is at bottom of valley where it can pool, above the spark plug's threads and gasket.

Edited by dom

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Mechanic said oil in spark plug valleys. He also said when I asked there was no oil on spark plugs. Is that possible.

Valve cover gasket stops oil from getting into spark plug valleys.

Thanks Dom.

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There may be some oil in the valley, but not enough to drain down on the spark plug.

 

When asked is there was oil on spark plug, a mechanic will typically relate to the sparking end which is more relevant to the engine's state of health.

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Ok so it is true I have oil in spark plug valleys but not on spark plugs.

That's what he told me. I have oil in the valleys and not on spark plugs

I never heard of spark plug valleys before. I do not even know if the valleys are something that gets replaced.

How do you stop it from getting into the valley.

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Most of the spark plug is covered by the coil on plug, or spark plug boot... Some oil can migrate up the spark plug threads from the combustion chamber is it's not tight enough and/or leaking at spark plug gasket.

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Valleys are simply holes (bores or cylinders) in your valve cover and in the engine head.... Valleys are not replaceable parts. Valleys are empty spaces cast into and part of the aluminum engine components.

Edited by dom

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Ok now I got you. Spark plug valleys are the holes where the spark plug sits.

Oil in the valleys means oil in the spark plug holes.

If mechanic says oil in the valleys but not on spark plugs he means: oil in the spark plug hole. Also there may or may not be oil on the top part of the spark plug but the firing end of plug that is at the bottom of hole has no oil on it.

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Sometimes, oil will get in there via spilled oil during an oil change, especially if you are not mindful of where the funnel is pointing, or if you try and free hand fill the crankcase without a funnel. The coil on plug igniters, that sit on the spark plugs, have a foam-rubber like gasket. If you spilled any oil, from the fill port, it could run along the upper length of the valve cover and weep past the COP igniter gaskets - dripping into the spark plug well.

 

Sometimes, oil will blow past the sparking end of the plug - if the plug isn't seated correctly. The sparking end may self-clean or just have some fluffy deposits, while the rest of it coats a few threads of the plug itself and the lower portion of the plug body.

 

Most likely, it is the valve cover gaskets - over time, they can harden and crack - causing oil to leak out.

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How can there be oil in the spark plug valleys (holes) and not any oil on the spark plugs.

That's what I want to know. My mechanic Tom said oil can be in the valley aka hole but not on the spark plug because the plugs are down deep under the valley. I have an idea what he means but not totally sure.

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Where on the spark plug? On the body that sits inside the plug well or the part that inside the combustion chamber? If you spilled oil on the valvecover, but the way it is shaped, oil could get wicked into the plug tubes and could coat the body of the plug (hex) part. That is assuming there is a fair amount of oil, that dripped from the top. A small amount may only partially coat the plug well and not actually make contact with the plug.

 

Same thing could happen with the a leaking valvecover, as alluded to other posters here. If a small amount of oil leaked past the gasket, it may only come partway down the plug hole and not actually touch the plug.

 

Also depends on when the oil made its way to the plug well. Eventually, given enough time, oil will pool at the bottom of the plug well from the force of gravity acting upon it. Even a tiny amount will be pulled to the bottom.

 

What did the mechanic say he wanted to do to remedy this situation? Or did he just note there was oil in the plug well.

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