Apple I-Mac moisture behind monitor & hot monitor

Hello,I have recently purchased I-mac 10.6.4 version 20" monitor. After 2 weeks use monitor screen had blurred image of printed matl in center of screen. Apple tech suggested take to computer tech approved by them in our area. Problem was moisture in monitor - glass was removed and moisture taken out. Area affected was about 3" x 2" in center of monitor. two weeks later I am having same problem. Also noted monitor became very hot after on awhile, uncomfortable to hold on top of monitor. Apple says this is normal????