Is it OK to leave the side of my computer case open with a fan blowing on it?

Guitarchim

Honorable
Feb 5, 2014
17
0
10,510
My computer is a little old business computer with no fan in it. I got a new card with no fan on it and when I play games it goes up to 80-85c and then screen goes blank. I opened up the side of the case and had a little fan blowing on it but I was wondering if this is a bad idea. I would only do this while gaming but while not gaming I'll would close it back up.