Lately I've been hearing a studdering noise from my engine, then poof a huge cloud of gray smoke would come out from behind my car. My car isn't over-heating, but I do see bubbles coming out of my radiator when someone revs my motor. My oil is dissipating little by little too.

I'm not sure if it's a blown head gasket or just running rich. Also, as I pulled out my spark plugs, I found that all their threads had liquid on them, I'm not sure if the liquid was gasoline, oil or coolant. Please help me diagnose my engine, please!! Thanks in advance.

 

I don't know what gray means, I know blue-ish means burning oil, which it sound like you are doing. White means burning coolant. Maybe you have both? That would suck, hope it turns out good.

 

valve seals might be going.