I had to drive my mercedes CLK 320 trough flood. And engine makes strange noice, what can it be?

The sound is most probably coming from vent, most probably it is touching something, but I wonder could I Have some other problems/ ANd how do I know if engine is hydrolocked? Everything functions OK, except that sound and engine sign turned up. (no beeps though)
P.S. The water only covered wheels of the car, not the hood.