I did this once. /forums/images/graemlins/tongue.gif
I got stuck in a mud/water pit and left the truck running the whole time. When I got pulled out, the truck ran like it had no power at all. Drove it home slowly and did the inspection in the garage.
Turns out the motor was half submerged in the water. Water had gotten into the crankcase thru the harmonic balancers seal, on the timing cover, down there. That was the only place the water could have gotten in since everything else was not under.
When the motor is spinning, the balancer is riding the seal, this causes a heat build-up therefore when cold water meets it, the seal will not do its job. Water will seep in and fill the crankcase up.
Luckily for me, all I had to do was drain the pan and drop the oil filter and install/pour all new in again. I did this 3 times before calling it finished. Just wanted to make sure all the water was flushed.
I even pulled the plugs before starting it again to make sure the water was not in the cylinders. Lucky there wasnt. Today the motor still runs fine. /forums/images/graemlins/wink.gif