2004 frontier engine noise

I have a 3.3 sc since new and its ben great with no problems so far. I do use the truck and i love fourwheelin. not sure if its relivent or not, but i drove through a water hole few days ago, shortley after a faint noise came about which grew noticeably louder in the engine. to me it sounds like a dry bearing ,something like a bad pilot bearing in a manual transmission. the noies is louder at the bottom end of the motor and theres a strong smell of fuel in the relitively new oil. what could it be?