Cooling Fan

I hit a rather large bump the other day in my '88 420SEL, and I didn't notice it at first, but when I started the car later there was a loud kind of clacking noise from my engine. I located the noise the the black plastic housing around the cooling fan, which had been dislodged, and the edge was hitting the bottom of the fan. I pushed it back down to where i assumed it was supposed to be so it wasn't hitting the fan, but I'm not too sure it won't happen again, it doesn't seem to be attached very well.

I noticed only two clips at the top holding it in, should there be anything else holding it? It doesn't feel very secure.

I don't even understand why it would come dislodged, and the noise really scared me. It thought it was something more serious.